From eb0bf1fd7a33330425a12420e5d948ca6e88d74f Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Tue, 26 Oct 2021 00:37:52 -0700
Subject: [PATCH 01/47] simple_playback api from nrf sdk

---
 embassy-nrf/src/pwm.rs               | 167 ++++++++++++++++++++++++++-
 embassy-nrf/src/util.rs              |   4 +-
 examples/nrf/src/bin/pwm_sequence.rs |  41 +++++++
 3 files changed, 207 insertions(+), 5 deletions(-)
 create mode 100644 examples/nrf/src/bin/pwm_sequence.rs

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 5e996e88..ccab6f48 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -9,7 +9,8 @@ use embassy_hal_common::unborrow;
 use crate::gpio::sealed::Pin as _;
 use crate::gpio::OptionalPin as GpioOptionalPin;
 use crate::interrupt::Interrupt;
-use crate::pac;
+use crate::util::slice_in_ram_or;
+use crate::{pac, EASY_DMA_SIZE};
 
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum Prescaler {
@@ -23,11 +24,57 @@ pub enum Prescaler {
     Div128,
 }
 
-/// Interface to the UARTE peripheral
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum SequenceLoad {
+    Common,
+    Grouped,
+    Individual,
+    Waveform,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum CounterMode {
+    Up,
+    UpAndDown,
+}
+
+/// Interface to the PWM peripheral
 pub struct Pwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
+// Configure an infinite looping sequence for `simple_playback`
+pub struct LoopingConfig<'a> {
+    /// Selects up mode or up-and-down mode for the counter
+    pub counter_mode: CounterMode,
+    // top value to be compared against buffer values
+    pub top: u16,
+    /// Configuration for PWM_CLK
+    pub prescaler: Prescaler,
+    /// In ram buffer to be played back
+    pub sequence: &'a [u16],
+    /// Common Mode means seq in buffer will be used across all channels
+    /// Individual Mode buffer holds [ch0_0, ch1_0, ch2_0, ch3_0, ch0_1, ch1_1,
+    /// ch2_1, ch3_1 ... ch0_n, ch1_n, ch2_n, ch3_n]
+    pub sequence_load: SequenceLoad,
+    /// will instruct a new RAM stored pulse width value on every (N+1)th PWM
+    /// period. Setting the register to zero will result in a new duty cycle
+    /// update every PWM period as long as the minimum PWM period is observed.
+    pub repeats: u32,
+    /// enddelay PWM period delays between last period on sequence 0 before repeating
+    pub enddelay: u32,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum Error {
+    Seq0BufferTooLong,
+    Seq1BufferTooLong,
+    /// EasyDMA can only read from data memory, read only buffers in flash will fail.
+    DMABufferNotInDataMemory,
+}
+
 impl<'d, T: Instance> Pwm<'d, T> {
     /// Creates the interface to a UARTE instance.
     /// Sets the baud rate, parity and assigns the pins to the UARTE peripheral.
@@ -99,6 +146,120 @@ impl<'d, T: Instance> Pwm<'d, T> {
         }
     }
 
+    pub fn simple_playback(
+        _pwm: impl Unborrow<Target = T> + 'd,
+        ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch1: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch2: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch3: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        config: LoopingConfig,
+        count: u16,
+    ) -> Result<Self, Error> {
+        slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
+
+        if config.sequence.len() > EASY_DMA_SIZE {
+            return Err(Error::Seq0BufferTooLong);
+        }
+
+        unborrow!(ch0, ch1, ch2, ch3);
+
+        let odd: bool = count & 1 == 1;
+
+        let r = T::regs();
+
+        if let Some(pin) = ch0.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+            r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
+        }
+        if let Some(pin) = ch1.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+            r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
+        }
+        if let Some(pin) = ch2.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+            r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
+        }
+        if let Some(pin) = ch3.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+            r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
+        }
+
+        r.enable.write(|w| w.enable().enabled());
+
+        r.mode
+            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
+        r.prescaler
+            .write(|w| w.prescaler().bits(config.prescaler as u8));
+        r.countertop
+            .write(|w| unsafe { w.countertop().bits(config.top) });
+
+        r.decoder.write(|w| {
+            w.load().bits(config.sequence_load as u8);
+            w.mode().refresh_count()
+        });
+
+        r.seq0
+            .ptr
+            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+        r.seq0
+            .cnt
+            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+        r.seq0.refresh.write(|w| unsafe { w.bits(config.repeats) });
+        r.seq0
+            .enddelay
+            .write(|w| unsafe { w.bits(config.enddelay) });
+
+        r.seq1
+            .ptr
+            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+        r.seq1
+            .cnt
+            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+        r.seq1.refresh.write(|w| unsafe { w.bits(config.repeats) });
+        r.seq1
+            .enddelay
+            .write(|w| unsafe { w.bits(config.enddelay) });
+
+        let mut loop_: u16 = count / 2;
+        if odd {
+            loop_ += 1;
+        }
+
+        r.loop_.write(|w| unsafe { w.cnt().bits(loop_) });
+
+        if odd {
+            r.shorts.write(|w| w.loopsdone_seqstart1().set_bit());
+        } else {
+            r.shorts.write(|w| w.loopsdone_seqstart0().set_bit());
+        }
+
+        // tasks_seqstart doesnt exist in all svds so write its bit instead
+        if odd {
+            r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+        } else {
+            r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+        }
+
+        Ok(Self {
+            phantom: PhantomData,
+        })
+    }
+
+    /// Stop playback
+    #[inline(always)]
+    pub fn stop(&self) {
+        let r = T::regs();
+
+        r.shorts.write(|w| unsafe { w.bits(0x0) });
+
+        // tasks_stop doesnt exist in all svds so write its bit instead
+        r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
+    }
+
     /// Enables the PWM generator.
     #[inline(always)]
     pub fn enable(&self) {
@@ -128,7 +289,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         T::regs().prescaler.write(|w| w.prescaler().bits(div as u8));
     }
 
-    /// Sets the PWM clock prescaler.
+    /// Gets the PWM clock prescaler.
     #[inline(always)]
     pub fn prescaler(&self) -> Prescaler {
         match T::regs().prescaler.read().prescaler().bits() {
diff --git a/embassy-nrf/src/util.rs b/embassy-nrf/src/util.rs
index 344fb01f..d17ec503 100644
--- a/embassy-nrf/src/util.rs
+++ b/embassy-nrf/src/util.rs
@@ -2,14 +2,14 @@ const SRAM_LOWER: usize = 0x2000_0000;
 const SRAM_UPPER: usize = 0x3000_0000;
 
 /// Does this slice reside entirely within RAM?
-pub(crate) fn slice_in_ram(slice: &[u8]) -> bool {
+pub(crate) fn slice_in_ram<T>(slice: &[T]) -> bool {
     let ptr = slice.as_ptr() as usize;
     ptr >= SRAM_LOWER && (ptr + slice.len()) < SRAM_UPPER
 }
 
 /// Return an error if slice is not in RAM.
 #[cfg(not(feature = "nrf51"))]
-pub(crate) fn slice_in_ram_or<T>(slice: &[u8], err: T) -> Result<(), T> {
+pub(crate) fn slice_in_ram_or<T, E>(slice: &[T], err: E) -> Result<(), E> {
     if slice.len() == 0 || slice_in_ram(slice) {
         Ok(())
     } else {
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
new file mode 100644
index 00000000..93ee9f5b
--- /dev/null
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -0,0 +1,41 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::gpio::NoPin;
+use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::Peripherals;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let seq_values: [u16; 2] = [0, 0x8000];
+
+    let config = LoopingConfig {
+        counter_mode: CounterMode::Up,
+        top: 31250,
+        prescaler: Prescaler::Div128,
+        sequence: &seq_values,
+        sequence_load: SequenceLoad::Common,
+        repeats: 1,
+        enddelay: 0,
+    };
+
+    let pwm = unwrap!(Pwm::simple_playback(
+        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config, 1
+    ));
+    info!("pwm started!");
+
+    Timer::after(Duration::from_millis(10000)).await;
+
+    pwm.stop();
+    info!("pwm stopped!");
+
+    loop {
+        Timer::after(Duration::from_millis(1000)).await;
+    }
+}

From 1d1d8a848e165e2754720fa442571782616cb822 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Fri, 29 Oct 2021 16:39:41 -0700
Subject: [PATCH 02/47] simplify api, more interesting example

---
 embassy-nrf/src/pwm.rs               | 22 +++-------------------
 examples/nrf/src/bin/pwm_sequence.rs | 14 +++++++-------
 2 files changed, 10 insertions(+), 26 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index ccab6f48..64b5e547 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -153,7 +153,6 @@ impl<'d, T: Instance> Pwm<'d, T> {
         ch2: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         ch3: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         config: LoopingConfig,
-        count: u16,
     ) -> Result<Self, Error> {
         slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
 
@@ -163,8 +162,6 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
         unborrow!(ch0, ch1, ch2, ch3);
 
-        let odd: bool = count & 1 == 1;
-
         let r = T::regs();
 
         if let Some(pin) = ch0.pin_mut() {
@@ -224,25 +221,12 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .enddelay
             .write(|w| unsafe { w.bits(config.enddelay) });
 
-        let mut loop_: u16 = count / 2;
-        if odd {
-            loop_ += 1;
-        }
+        r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
 
-        r.loop_.write(|w| unsafe { w.cnt().bits(loop_) });
-
-        if odd {
-            r.shorts.write(|w| w.loopsdone_seqstart1().set_bit());
-        } else {
-            r.shorts.write(|w| w.loopsdone_seqstart0().set_bit());
-        }
+        r.shorts.write(|w| w.loopsdone_seqstart1().set_bit());
 
         // tasks_seqstart doesnt exist in all svds so write its bit instead
-        if odd {
-            r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
-        } else {
-            r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-        }
+        r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
 
         Ok(Self {
             phantom: PhantomData,
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 93ee9f5b..bc356c28 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,26 +7,26 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::gpio::NoPin;
 use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let seq_values: [u16; 2] = [0, 0x8000];
-
+    let seq_values: [u16; 16] = [
+        0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
+    ];
     let config = LoopingConfig {
         counter_mode: CounterMode::Up,
-        top: 31250,
+        top: 15625,
         prescaler: Prescaler::Div128,
         sequence: &seq_values,
-        sequence_load: SequenceLoad::Common,
-        repeats: 1,
+        sequence_load: SequenceLoad::Individual,
+        repeats: 0,
         enddelay: 0,
     };
 
     let pwm = unwrap!(Pwm::simple_playback(
-        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config, 1
+        p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
     ));
     info!("pwm started!");
 

From ef95441442e0ccab0ac6d62264dedb7254d4cb84 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Fri, 29 Oct 2021 17:09:34 -0700
Subject: [PATCH 03/47] a runtime generated sin table example

---
 examples/nrf/Cargo.toml                |  1 +
 examples/nrf/src/bin/pwm_simple_sin.rs | 41 ++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 examples/nrf/src/bin/pwm_simple_sin.rs

diff --git a/examples/nrf/Cargo.toml b/examples/nrf/Cargo.toml
index b89aa513..e0025b73 100644
--- a/examples/nrf/Cargo.toml
+++ b/examples/nrf/Cargo.toml
@@ -31,3 +31,4 @@ panic-probe = { version = "0.2.0", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 rand = { version = "0.8.4", default-features = false }
 embedded-storage = "0.2.0"
+micromath = "2.0.0"
\ No newline at end of file
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
new file mode 100644
index 00000000..866202a4
--- /dev/null
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -0,0 +1,41 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+#![feature(array_from_fn)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::gpio::NoPin;
+use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::Peripherals;
+use micromath::F32Ext;
+
+const W1: f32 = core::f32::consts::PI / 128.0;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    // probably not best use of resources to create the table at runtime, but makes testing fast
+    let seq_values: [u16; 220] = core::array::from_fn(|n| ((W1 * n as f32).sin() * 10000.0) as u16);
+
+    let config = LoopingConfig {
+        counter_mode: CounterMode::UpAndDown,
+        top: 12000,
+        prescaler: Prescaler::Div16,
+        sequence: &seq_values,
+        sequence_load: SequenceLoad::Common,
+        repeats: 0,
+        enddelay: 0,
+    };
+
+    let _pwm = unwrap!(Pwm::simple_playback(
+        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
+    ));
+    info!("pwm started!");
+
+    loop {
+        Timer::after(Duration::from_millis(1000)).await;
+    }
+}

From 6d8198a46ae20be24c84fbb07d474d4eb507ac4d Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sat, 30 Oct 2021 11:33:10 -0700
Subject: [PATCH 04/47] move psel back out of if

---
 embassy-nrf/src/pwm.rs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 64b5e547..d834b130 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -167,24 +167,28 @@ impl<'d, T: Instance> Pwm<'d, T> {
         if let Some(pin) = ch0.pin_mut() {
             pin.set_low();
             pin.conf().write(|w| w.dir().output());
-            r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
         }
+
         if let Some(pin) = ch1.pin_mut() {
             pin.set_low();
             pin.conf().write(|w| w.dir().output());
-            r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
         }
         if let Some(pin) = ch2.pin_mut() {
             pin.set_low();
             pin.conf().write(|w| w.dir().output());
-            r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
         }
         if let Some(pin) = ch3.pin_mut() {
             pin.set_low();
             pin.conf().write(|w| w.dir().output());
-            r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
         }
 
+        // if NoPin provided writes disconnected (top bit 1) 0x80000000 else
+        // writes pin number ex 13 (0x0D) which is connected (top bit 0)
+        r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
+        r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
+        r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
+        r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
+
         r.enable.write(|w| w.enable().enabled());
 
         r.mode
@@ -323,6 +327,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 impl<'a, T: Instance> Drop for Pwm<'a, T> {
     fn drop(&mut self) {
         let r = T::regs();
+
         r.enable.write(|w| w.enable().disabled());
 
         info!("pwm drop: done");

From ee8f76537b2dd8e886f44bd7e43d4ba9fd767778 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sat, 30 Oct 2021 11:33:28 -0700
Subject: [PATCH 05/47] at least stop on drop

---
 embassy-nrf/src/pwm.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index d834b130..42294312 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -328,6 +328,7 @@ impl<'a, T: Instance> Drop for Pwm<'a, T> {
     fn drop(&mut self) {
         let r = T::regs();
 
+        self.stop();
         r.enable.write(|w| w.enable().disabled());
 
         info!("pwm drop: done");

From 763e250dfea4425912674ed68d77c3291b0505e0 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sat, 30 Oct 2021 16:16:10 -0700
Subject: [PATCH 06/47] add ability to configure loop count from 1 to infinite

---
 embassy-nrf/src/pwm.rs                 | 69 +++++++++++++++++++-------
 examples/nrf/src/bin/pwm_sequence.rs   | 13 ++---
 examples/nrf/src/bin/pwm_simple_sin.rs | 12 +++--
 3 files changed, 65 insertions(+), 29 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 42294312..3f05ed58 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -24,10 +24,13 @@ pub enum Prescaler {
     Div128,
 }
 
+/// How a sequence is read from RAM and is spread to the compare register
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum SequenceLoad {
+    /// sequence in buffer will be used across all channels
     Common,
     Grouped,
+    /// buffer holds [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
     Individual,
     Waveform,
 }
@@ -43,26 +46,32 @@ pub struct Pwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum LoopMode {
+    // Repeat n additional times after the first
+    Additional(u16),
+    /// Repeat until `stop` is called
+    Infinite,
+}
+
 // Configure an infinite looping sequence for `simple_playback`
 pub struct LoopingConfig<'a> {
     /// Selects up mode or up-and-down mode for the counter
     pub counter_mode: CounterMode,
-    // top value to be compared against buffer values
+    // Top value to be compared against buffer values
     pub top: u16,
     /// Configuration for PWM_CLK
     pub prescaler: Prescaler,
     /// In ram buffer to be played back
     pub sequence: &'a [u16],
-    /// Common Mode means seq in buffer will be used across all channels
-    /// Individual Mode buffer holds [ch0_0, ch1_0, ch2_0, ch3_0, ch0_1, ch1_1,
-    /// ch2_1, ch3_1 ... ch0_n, ch1_n, ch2_n, ch3_n]
+    /// How a sequence is read from RAM and is spread to the compare register
     pub sequence_load: SequenceLoad,
-    /// will instruct a new RAM stored pulse width value on every (N+1)th PWM
-    /// period. Setting the register to zero will result in a new duty cycle
-    /// update every PWM period as long as the minimum PWM period is observed.
-    pub repeats: u32,
-    /// enddelay PWM period delays between last period on sequence 0 before repeating
+    /// Number of additional PWM periods between samples loaded into compare register
+    pub refresh: u32,
+    /// Number of additional PWM periods after the sequence ends
     pub enddelay: u32,
+    /// How many times to repeat the sequence
+    pub additional_loops: LoopMode,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -146,6 +155,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         }
     }
 
+    /// Returns a configured pwm that has had start called on it
     pub fn simple_playback(
         _pwm: impl Unborrow<Target = T> + 'd,
         ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
@@ -209,7 +219,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.seq0
             .cnt
             .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
-        r.seq0.refresh.write(|w| unsafe { w.bits(config.repeats) });
+        r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq0
             .enddelay
             .write(|w| unsafe { w.bits(config.enddelay) });
@@ -220,17 +230,42 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.seq1
             .cnt
             .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
-        r.seq1.refresh.write(|w| unsafe { w.bits(config.repeats) });
+        r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq1
             .enddelay
             .write(|w| unsafe { w.bits(config.enddelay) });
 
-        r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
+        match config.additional_loops {
+            LoopMode::Additional(0) => {
+                r.loop_.write(|w| w.cnt().disabled());
+                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+            }
+            LoopMode::Additional(n) => {
+                let times = (n / 2) + 1;
 
-        r.shorts.write(|w| w.loopsdone_seqstart1().set_bit());
+                r.loop_.write(|w| unsafe { w.cnt().bits(times) });
+                r.shorts.write(|w| {
+                    w.loopsdone_seqstart1().enabled();
+                    w.loopsdone_seqstart0().disabled();
+                    w.loopsdone_stop().enabled()
+                });
 
-        // tasks_seqstart doesnt exist in all svds so write its bit instead
-        r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+                if n & 1 == 1 {
+                    r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+                } else {
+                    r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+                }
+            }
+
+            LoopMode::Infinite => {
+                r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
+                r.shorts.write(|w| {
+                    w.loopsdone_seqstart1().enabled();
+                    w.loopsdone_seqstart0().disabled()
+                });
+                r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+            }
+        }
 
         Ok(Self {
             phantom: PhantomData,
@@ -326,10 +361,8 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
 impl<'a, T: Instance> Drop for Pwm<'a, T> {
     fn drop(&mut self) {
-        let r = T::regs();
-
         self.stop();
-        r.enable.write(|w| w.enable().disabled());
+        self.disable();
 
         info!("pwm drop: done");
 
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index bc356c28..8b7aeddc 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,7 +7,7 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
@@ -15,26 +15,23 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     let seq_values: [u16; 16] = [
         0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
     ];
+
     let config = LoopingConfig {
         counter_mode: CounterMode::Up,
         top: 15625,
         prescaler: Prescaler::Div128,
         sequence: &seq_values,
         sequence_load: SequenceLoad::Individual,
-        repeats: 0,
+        refresh: 0,
         enddelay: 0,
+        additional_loops: LoopMode::Additional(5),
     };
 
-    let pwm = unwrap!(Pwm::simple_playback(
+    let _pwm = unwrap!(Pwm::simple_playback(
         p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
     ));
     info!("pwm started!");
 
-    Timer::after(Duration::from_millis(10000)).await;
-
-    pwm.stop();
-    info!("pwm stopped!");
-
     loop {
         Timer::after(Duration::from_millis(1000)).await;
     }
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 866202a4..3fbfc960 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -9,7 +9,7 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
 use embassy_nrf::Peripherals;
 use micromath::F32Ext;
 
@@ -26,15 +26,21 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         prescaler: Prescaler::Div16,
         sequence: &seq_values,
         sequence_load: SequenceLoad::Common,
-        repeats: 0,
+        refresh: 0,
         enddelay: 0,
+        additional_loops: LoopMode::Infinite,
     };
 
-    let _pwm = unwrap!(Pwm::simple_playback(
+    let pwm = unwrap!(Pwm::simple_playback(
         p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
     ));
     info!("pwm started!");
 
+    Timer::after(Duration::from_millis(20000)).await;
+
+    pwm.stop();
+    info!("pwm stopped!");
+
     loop {
         Timer::after(Duration::from_millis(1000)).await;
     }

From 96df2fdb4343c701549bc77fa9bb06352e439f81 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sat, 30 Oct 2021 16:23:45 -0700
Subject: [PATCH 07/47] lost comment

---
 embassy-nrf/src/pwm.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 3f05ed58..83d0bdae 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -251,8 +251,10 @@ impl<'d, T: Instance> Pwm<'d, T> {
                 });
 
                 if n & 1 == 1 {
+                    // tasks_seqstart doesnt exist in all svds so write its bit instead
                     r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
                 } else {
+                    // tasks_seqstart doesnt exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
                 }
             }

From 78e382c9aa421b8319dcf1c9ea44ae046c1a019d Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sun, 31 Oct 2021 23:00:33 -0700
Subject: [PATCH 08/47] stop->sequence_stop

---
 embassy-nrf/src/pwm.rs                 | 4 ++--
 examples/nrf/src/bin/pwm_simple_sin.rs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 83d0bdae..8d4a9d8b 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -276,7 +276,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
     /// Stop playback
     #[inline(always)]
-    pub fn stop(&self) {
+    pub fn sequence_stop(&self) {
         let r = T::regs();
 
         r.shorts.write(|w| unsafe { w.bits(0x0) });
@@ -363,7 +363,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
 impl<'a, T: Instance> Drop for Pwm<'a, T> {
     fn drop(&mut self) {
-        self.stop();
+        self.sequence_stop();
         self.disable();
 
         info!("pwm drop: done");
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 3fbfc960..c7d85381 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -38,7 +38,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
 
     Timer::after(Duration::from_millis(20000)).await;
 
-    pwm.stop();
+    pwm.sequence_stop();
     info!("pwm stopped!");
 
     loop {

From d98a1707b974660b585de1015787c0e5066d81d2 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Sun, 31 Oct 2021 23:28:26 -0700
Subject: [PATCH 09/47] using write dont need to clear

---
 embassy-nrf/src/pwm.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 8d4a9d8b..9672e6f2 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -246,7 +246,6 @@ impl<'d, T: Instance> Pwm<'d, T> {
                 r.loop_.write(|w| unsafe { w.cnt().bits(times) });
                 r.shorts.write(|w| {
                     w.loopsdone_seqstart1().enabled();
-                    w.loopsdone_seqstart0().disabled();
                     w.loopsdone_stop().enabled()
                 });
 

From 72fa1c8482270e3004b7ef717a45cfe0bd3cde97 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 00:21:17 -0700
Subject: [PATCH 10/47] fix additional to remove stuck light at end

---
 embassy-nrf/src/pwm.rs | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 9672e6f2..64a25f23 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -236,18 +236,19 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .write(|w| unsafe { w.bits(config.enddelay) });
 
         match config.additional_loops {
+            // just the one time, no loop count
             LoopMode::Additional(0) => {
                 r.loop_.write(|w| w.cnt().disabled());
+                // tasks_seqstart doesnt exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
+            // loop count is how many times to play BOTH sequences
+            // the one time + 1 = 2 total, play the sequence once starting from seq0
+            // the one time + 2 = 3 total, playing the sequence twice would be too much, but we can start on seq1 to subtract one
+            // the one time + 3 = 4 total, play the sequence twice starting from seq0
             LoopMode::Additional(n) => {
                 let times = (n / 2) + 1;
-
                 r.loop_.write(|w| unsafe { w.cnt().bits(times) });
-                r.shorts.write(|w| {
-                    w.loopsdone_seqstart1().enabled();
-                    w.loopsdone_stop().enabled()
-                });
 
                 if n & 1 == 1 {
                     // tasks_seqstart doesnt exist in all svds so write its bit instead
@@ -257,13 +258,10 @@ impl<'d, T: Instance> Pwm<'d, T> {
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
                 }
             }
-
             LoopMode::Infinite => {
                 r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
-                r.shorts.write(|w| {
-                    w.loopsdone_seqstart1().enabled();
-                    w.loopsdone_seqstart0().disabled()
-                });
+                r.shorts.write(|w| w.loopsdone_seqstart1().enabled());
+                // tasks_seqstart doesnt exist in all svds so write its bit instead
                 r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
             }
         }

From 7b092f463e630e7d8725f6af2d0138b608050b1f Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 00:30:42 -0700
Subject: [PATCH 11/47] clarify infinite

---
 embassy-nrf/src/pwm.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 64a25f23..5ed9cf14 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -258,11 +258,12 @@ impl<'d, T: Instance> Pwm<'d, T> {
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
                 }
             }
+            // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
             LoopMode::Infinite => {
                 r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
-                r.shorts.write(|w| w.loopsdone_seqstart1().enabled());
+                r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
                 // tasks_seqstart doesnt exist in all svds so write its bit instead
-                r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
         }
 

From 14dc524b84b28cfa6f8a9649c38173d6a1977a9e Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 01:20:01 -0700
Subject: [PATCH 12/47] documentation

---
 embassy-nrf/src/pwm.rs                 | 19 ++++++++++++-------
 examples/nrf/src/bin/pwm_sequence.rs   |  2 +-
 examples/nrf/src/bin/pwm_simple_sin.rs |  2 +-
 3 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 5ed9cf14..5f3a4df8 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -27,11 +27,16 @@ pub enum Prescaler {
 /// How a sequence is read from RAM and is spread to the compare register
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum SequenceLoad {
-    /// sequence in buffer will be used across all channels
+    /// Provided sequence will be used across all channels
     Common,
+    /// Provided sequence contains grouped values for each channel ex:
+    /// [ch0_0_and_ch1_0, ch2_0_and_ch3_0, ... ch0_n_and_ch1_n, ch2_n_and_ch3_n]
     Grouped,
-    /// buffer holds [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
+    /// Provided sequence contains individual values for each channel ex:
+    /// [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
     Individual,
+    /// Similar to Individual mode, but only three channels are used. The fourth
+    /// value is loaded into the pulse generator counter as its top value.
     Waveform,
 }
 
@@ -66,10 +71,10 @@ pub struct LoopingConfig<'a> {
     pub sequence: &'a [u16],
     /// How a sequence is read from RAM and is spread to the compare register
     pub sequence_load: SequenceLoad,
-    /// Number of additional PWM periods between samples loaded into compare register
+    /// Number of additional PWM periods to delay between each sequence sample
     pub refresh: u32,
-    /// Number of additional PWM periods after the sequence ends
-    pub enddelay: u32,
+    /// Number of additional PWM periods after the sequence ends before starting the next sequence
+    pub end_delay: u32,
     /// How many times to repeat the sequence
     pub additional_loops: LoopMode,
 }
@@ -222,7 +227,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq0
             .enddelay
-            .write(|w| unsafe { w.bits(config.enddelay) });
+            .write(|w| unsafe { w.bits(config.end_delay) });
 
         r.seq1
             .ptr
@@ -233,7 +238,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq1
             .enddelay
-            .write(|w| unsafe { w.bits(config.enddelay) });
+            .write(|w| unsafe { w.bits(config.end_delay) });
 
         match config.additional_loops {
             // just the one time, no loop count
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 8b7aeddc..1c5ab268 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -23,7 +23,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence: &seq_values,
         sequence_load: SequenceLoad::Individual,
         refresh: 0,
-        enddelay: 0,
+        end_delay: 0,
         additional_loops: LoopMode::Additional(5),
     };
 
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index c7d85381..909b8bf3 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -27,7 +27,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence: &seq_values,
         sequence_load: SequenceLoad::Common,
         refresh: 0,
-        enddelay: 0,
+        end_delay: 1,
         additional_loops: LoopMode::Infinite,
     };
 

From 48673e27cd5e1f879d758533bec020bc2e7cc0c2 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 01:15:04 -0700
Subject: [PATCH 13/47] fix max sequence length

---
 embassy-nrf/src/pwm.rs | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 5f3a4df8..19b653ca 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -9,9 +9,10 @@ use embassy_hal_common::unborrow;
 use crate::gpio::sealed::Pin as _;
 use crate::gpio::OptionalPin as GpioOptionalPin;
 use crate::interrupt::Interrupt;
+use crate::pac;
 use crate::util::slice_in_ram_or;
-use crate::{pac, EASY_DMA_SIZE};
 
+/// PWM Base clock is system clock (16MHz) divided by prescaler
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum Prescaler {
     Div1,
@@ -24,7 +25,7 @@ pub enum Prescaler {
     Div128,
 }
 
-/// How a sequence is read from RAM and is spread to the compare register
+/// How the sequence values are distributed across the channels
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum SequenceLoad {
     /// Provided sequence will be used across all channels
@@ -42,7 +43,9 @@ pub enum SequenceLoad {
 
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum CounterMode {
+    /// Up counter (edge-aligned PWM duty cycle)
     Up,
+    /// Up and down counter (center-aligned PWM duty cycle)
     UpAndDown,
 }
 
@@ -53,13 +56,13 @@ pub struct Pwm<'d, T: Instance> {
 
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum LoopMode {
-    // Repeat n additional times after the first
+    /// Repeat n additional times after the first
     Additional(u16),
-    /// Repeat until `stop` is called
+    /// Repeat until `stop` is called.
     Infinite,
 }
 
-// Configure an infinite looping sequence for `simple_playback`
+/// Configure an infinite looping sequence for `simple_playback`
 pub struct LoopingConfig<'a> {
     /// Selects up mode or up-and-down mode for the counter
     pub counter_mode: CounterMode,
@@ -83,8 +86,8 @@ pub struct LoopingConfig<'a> {
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
 #[non_exhaustive]
 pub enum Error {
-    Seq0BufferTooLong,
-    Seq1BufferTooLong,
+    /// Max Sequence size is 32767
+    SequenceTooLong,
     /// EasyDMA can only read from data memory, read only buffers in flash will fail.
     DMABufferNotInDataMemory,
 }
@@ -171,8 +174,8 @@ impl<'d, T: Instance> Pwm<'d, T> {
     ) -> Result<Self, Error> {
         slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
 
-        if config.sequence.len() > EASY_DMA_SIZE {
-            return Err(Error::Seq0BufferTooLong);
+        if config.sequence.len() > 32767 {
+            return Err(Error::SequenceTooLong);
         }
 
         unborrow!(ch0, ch1, ch2, ch3);

From 90be851e4b52703b4297615253bc7a89fdd03b9f Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 08:45:07 -0700
Subject: [PATCH 14/47] reduce complexity of loopmode

---
 embassy-nrf/src/pwm.rs                 | 40 +++++++++++++++-----------
 examples/nrf/src/bin/pwm_sequence.rs   |  2 +-
 examples/nrf/src/bin/pwm_simple_sin.rs |  4 +--
 3 files changed, 26 insertions(+), 20 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 19b653ca..8775c889 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -56,8 +56,8 @@ pub struct Pwm<'d, T: Instance> {
 
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum LoopMode {
-    /// Repeat n additional times after the first
-    Additional(u16),
+    /// Run sequence n Times total
+    Times(u16),
     /// Repeat until `stop` is called.
     Infinite,
 }
@@ -74,12 +74,12 @@ pub struct LoopingConfig<'a> {
     pub sequence: &'a [u16],
     /// How a sequence is read from RAM and is spread to the compare register
     pub sequence_load: SequenceLoad,
-    /// Number of additional PWM periods to delay between each sequence sample
+    /// Number of Times PWM periods to delay between each sequence sample
     pub refresh: u32,
-    /// Number of additional PWM periods after the sequence ends before starting the next sequence
+    /// Number of Times PWM periods after the sequence ends before starting the next sequence
     pub end_delay: u32,
-    /// How many times to repeat the sequence
-    pub additional_loops: LoopMode,
+    /// How many times to play the sequence
+    pub times: LoopMode,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -88,6 +88,8 @@ pub struct LoopingConfig<'a> {
 pub enum Error {
     /// Max Sequence size is 32767
     SequenceTooLong,
+    /// Min Sequence size is 1
+    SequenceTooShort,
     /// EasyDMA can only read from data memory, read only buffers in flash will fail.
     DMABufferNotInDataMemory,
 }
@@ -177,6 +179,9 @@ impl<'d, T: Instance> Pwm<'d, T> {
         if config.sequence.len() > 32767 {
             return Err(Error::SequenceTooLong);
         }
+        if let LoopMode::Times(0) = config.times {
+            return Err(Error::SequenceTooShort);
+        }
 
         unborrow!(ch0, ch1, ch2, ch3);
 
@@ -243,27 +248,28 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .enddelay
             .write(|w| unsafe { w.bits(config.end_delay) });
 
-        match config.additional_loops {
+        match config.times {
             // just the one time, no loop count
-            LoopMode::Additional(0) => {
+            LoopMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
                 // tasks_seqstart doesnt exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
             // loop count is how many times to play BOTH sequences
-            // the one time + 1 = 2 total, play the sequence once starting from seq0
-            // the one time + 2 = 3 total, playing the sequence twice would be too much, but we can start on seq1 to subtract one
-            // the one time + 3 = 4 total, play the sequence twice starting from seq0
-            LoopMode::Additional(n) => {
-                let times = (n / 2) + 1;
+            // 2 total  (1 x 2)
+            // 3 total, (2 x 2) - 1
+            LoopMode::Times(n) => {
+                let odd = n & 1 == 1;
+                let times = if odd { (n / 2) + 1 } else { n / 2 };
+
                 r.loop_.write(|w| unsafe { w.cnt().bits(times) });
 
-                if n & 1 == 1 {
-                    // tasks_seqstart doesnt exist in all svds so write its bit instead
-                    r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-                } else {
+                if odd {
                     // tasks_seqstart doesnt exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+                } else {
+                    // tasks_seqstart doesnt exist in all svds so write its bit instead
+                    r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
                 }
             }
             // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 1c5ab268..40ba7ab1 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -24,7 +24,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence_load: SequenceLoad::Individual,
         refresh: 0,
         end_delay: 0,
-        additional_loops: LoopMode::Additional(5),
+        times: LoopMode::Times(5),
     };
 
     let _pwm = unwrap!(Pwm::simple_playback(
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 909b8bf3..c1af0db8 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -27,8 +27,8 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence: &seq_values,
         sequence_load: SequenceLoad::Common,
         refresh: 0,
-        end_delay: 1,
-        additional_loops: LoopMode::Infinite,
+        end_delay: 0,
+        times: LoopMode::Infinite,
     };
 
     let pwm = unwrap!(Pwm::simple_playback(

From 12b2c5d5f70b836c853c000f036df2bdc255098d Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 08:54:07 -0700
Subject: [PATCH 15/47] better not as a constructor?

---
 embassy-nrf/src/pwm.rs                 | 60 ++++++--------------------
 examples/nrf/src/bin/pwm_sequence.rs   | 11 +++--
 examples/nrf/src/bin/pwm_simple_sin.rs | 11 +++--
 3 files changed, 22 insertions(+), 60 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 8775c889..d9d69170 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -55,7 +55,7 @@ pub struct Pwm<'d, T: Instance> {
 }
 
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
-pub enum LoopMode {
+pub enum SequenceMode {
     /// Run sequence n Times total
     Times(u16),
     /// Repeat until `stop` is called.
@@ -63,7 +63,7 @@ pub enum LoopMode {
 }
 
 /// Configure an infinite looping sequence for `simple_playback`
-pub struct LoopingConfig<'a> {
+pub struct SequenceConfig<'a> {
     /// Selects up mode or up-and-down mode for the counter
     pub counter_mode: CounterMode,
     // Top value to be compared against buffer values
@@ -79,7 +79,7 @@ pub struct LoopingConfig<'a> {
     /// Number of Times PWM periods after the sequence ends before starting the next sequence
     pub end_delay: u32,
     /// How many times to play the sequence
-    pub times: LoopMode,
+    pub times: SequenceMode,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -132,6 +132,9 @@ impl<'d, T: Instance> Pwm<'d, T> {
             pin.set_low();
             pin.conf().write(|w| w.dir().output());
         }
+
+        // if NoPin provided writes disconnected (top bit 1) 0x80000000 else
+        // writes pin number ex 13 (0x0D) which is connected (top bit 0)
         r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
         r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
         r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
@@ -166,54 +169,18 @@ impl<'d, T: Instance> Pwm<'d, T> {
     }
 
     /// Returns a configured pwm that has had start called on it
-    pub fn simple_playback(
-        _pwm: impl Unborrow<Target = T> + 'd,
-        ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
-        ch1: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
-        ch2: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
-        ch3: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
-        config: LoopingConfig,
-    ) -> Result<Self, Error> {
+    pub fn play_sequence(&self, config: SequenceConfig) -> Result<(), Error> {
         slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
 
         if config.sequence.len() > 32767 {
             return Err(Error::SequenceTooLong);
         }
-        if let LoopMode::Times(0) = config.times {
+        if let SequenceMode::Times(0) = config.times {
             return Err(Error::SequenceTooShort);
         }
 
-        unborrow!(ch0, ch1, ch2, ch3);
-
         let r = T::regs();
 
-        if let Some(pin) = ch0.pin_mut() {
-            pin.set_low();
-            pin.conf().write(|w| w.dir().output());
-        }
-
-        if let Some(pin) = ch1.pin_mut() {
-            pin.set_low();
-            pin.conf().write(|w| w.dir().output());
-        }
-        if let Some(pin) = ch2.pin_mut() {
-            pin.set_low();
-            pin.conf().write(|w| w.dir().output());
-        }
-        if let Some(pin) = ch3.pin_mut() {
-            pin.set_low();
-            pin.conf().write(|w| w.dir().output());
-        }
-
-        // if NoPin provided writes disconnected (top bit 1) 0x80000000 else
-        // writes pin number ex 13 (0x0D) which is connected (top bit 0)
-        r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
-        r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
-        r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
-        r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
-
-        r.enable.write(|w| w.enable().enabled());
-
         r.mode
             .write(|w| unsafe { w.bits(config.counter_mode as u32) });
         r.prescaler
@@ -250,7 +217,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
         match config.times {
             // just the one time, no loop count
-            LoopMode::Times(1) => {
+            SequenceMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
                 // tasks_seqstart doesnt exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
@@ -258,7 +225,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
             // loop count is how many times to play BOTH sequences
             // 2 total  (1 x 2)
             // 3 total, (2 x 2) - 1
-            LoopMode::Times(n) => {
+            SequenceMode::Times(n) => {
                 let odd = n & 1 == 1;
                 let times = if odd { (n / 2) + 1 } else { n / 2 };
 
@@ -273,17 +240,14 @@ impl<'d, T: Instance> Pwm<'d, T> {
                 }
             }
             // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
-            LoopMode::Infinite => {
+            SequenceMode::Infinite => {
                 r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
                 r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
                 // tasks_seqstart doesnt exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
         }
-
-        Ok(Self {
-            phantom: PhantomData,
-        })
+        Ok(())
     }
 
     /// Stop playback
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 40ba7ab1..066ab3c0 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,7 +7,7 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::pwm::{CounterMode, Prescaler, Pwm, SequenceConfig, SequenceLoad, SequenceMode};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
@@ -16,7 +16,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
     ];
 
-    let config = LoopingConfig {
+    let config = SequenceConfig {
         counter_mode: CounterMode::Up,
         top: 15625,
         prescaler: Prescaler::Div128,
@@ -24,12 +24,11 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence_load: SequenceLoad::Individual,
         refresh: 0,
         end_delay: 0,
-        times: LoopMode::Times(5),
+        times: SequenceMode::Times(5),
     };
 
-    let _pwm = unwrap!(Pwm::simple_playback(
-        p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
-    ));
+    let pwm = Pwm::new(p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14);
+    unwrap!(pwm.play_sequence(config));
     info!("pwm started!");
 
     loop {
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index c1af0db8..3c1bddbc 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -9,7 +9,7 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
+use embassy_nrf::pwm::{CounterMode, Prescaler, Pwm, SequenceConfig, SequenceLoad, SequenceMode};
 use embassy_nrf::Peripherals;
 use micromath::F32Ext;
 
@@ -20,7 +20,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     // probably not best use of resources to create the table at runtime, but makes testing fast
     let seq_values: [u16; 220] = core::array::from_fn(|n| ((W1 * n as f32).sin() * 10000.0) as u16);
 
-    let config = LoopingConfig {
+    let config = SequenceConfig {
         counter_mode: CounterMode::UpAndDown,
         top: 12000,
         prescaler: Prescaler::Div16,
@@ -28,12 +28,11 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence_load: SequenceLoad::Common,
         refresh: 0,
         end_delay: 0,
-        times: LoopMode::Infinite,
+        times: SequenceMode::Infinite,
     };
 
-    let pwm = unwrap!(Pwm::simple_playback(
-        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
-    ));
+    let pwm = Pwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
+    unwrap!(pwm.play_sequence(config));
     info!("pwm started!");
 
     Timer::after(Duration::from_millis(20000)).await;

From 5285179218a0d5137dc6c1c16f2d01617c310a0a Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 09:37:34 -0700
Subject: [PATCH 16/47] generalize new and change pwm example to a servo

---
 embassy-nrf/src/pwm.rs      |  22 +++----
 examples/nrf/src/bin/pwm.rs | 111 ++++++++++--------------------------
 2 files changed, 41 insertions(+), 92 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index d9d69170..31e8a3b6 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -95,14 +95,15 @@ pub enum Error {
 }
 
 impl<'d, T: Instance> Pwm<'d, T> {
-    /// Creates the interface to a UARTE instance.
-    /// Sets the baud rate, parity and assigns the pins to the UARTE peripheral.
+    /// Creates the interface to a PWM instance.
+    ///
+    /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
     ///
     /// # Safety
     ///
-    /// The returned API is safe unless you use `mem::forget` (or similar safe mechanisms)
-    /// on stack allocated buffers which which have been passed to [`send()`](Pwm::send)
-    /// or [`receive`](Pwm::receive).
+    /// The returned API is safe unless you use `mem::forget` (or similar safe
+    /// mechanisms) on stack allocated buffers which which have been passed to
+    /// [`send()`](Pwm::send) or [`receive`](Pwm::receive).
     #[allow(unused_unsafe)]
     pub fn new(
         _pwm: impl Unborrow<Target = T> + 'd,
@@ -141,7 +142,9 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
 
         // Disable all interrupts
+        r.intenset.reset();
         r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
+        r.shorts.reset();
 
         // Enable
         r.enable.write(|w| w.enable().enabled());
@@ -150,7 +153,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .ptr
             .write(|w| unsafe { w.bits(&s.duty as *const _ as u32) });
         r.seq0.cnt.write(|w| unsafe { w.bits(4) });
-        r.seq0.refresh.write(|w| unsafe { w.bits(32) });
+        r.seq0.refresh.write(|w| unsafe { w.bits(0) });
         r.seq0.enddelay.write(|w| unsafe { w.bits(0) });
 
         r.decoder.write(|w| {
@@ -158,9 +161,8 @@ impl<'d, T: Instance> Pwm<'d, T> {
             w.mode().refresh_count()
         });
         r.mode.write(|w| w.updown().up());
-        r.prescaler.write(|w| w.prescaler().div_1());
-        r.countertop
-            .write(|w| unsafe { w.countertop().bits(32767) });
+        r.prescaler.write(|w| w.prescaler().div_16());
+        r.countertop.write(|w| unsafe { w.countertop().bits(1000) });
         r.loop_.write(|w| w.cnt().disabled());
 
         Self {
@@ -255,7 +257,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
     pub fn sequence_stop(&self) {
         let r = T::regs();
 
-        r.shorts.write(|w| unsafe { w.bits(0x0) });
+        r.shorts.reset();
 
         // tasks_stop doesnt exist in all svds so write its bit instead
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
diff --git a/examples/nrf/src/bin/pwm.rs b/examples/nrf/src/bin/pwm.rs
index ab033eb5..aeda80be 100644
--- a/examples/nrf/src/bin/pwm.rs
+++ b/examples/nrf/src/bin/pwm.rs
@@ -7,95 +7,42 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
+use embassy_nrf::gpio::NoPin;
 use embassy_nrf::pwm::{Prescaler, Pwm};
 use embassy_nrf::Peripherals;
 
-// for i in range(1024): print(int((math.sin(i/512*math.pi)*0.4+0.5)**2*32767), ', ', end='')
-static DUTY: [u16; 1024] = [
-    8191, 8272, 8353, 8434, 8516, 8598, 8681, 8764, 8847, 8931, 9015, 9099, 9184, 9269, 9354, 9440,
-    9526, 9613, 9700, 9787, 9874, 9962, 10050, 10139, 10227, 10316, 10406, 10495, 10585, 10675,
-    10766, 10857, 10948, 11039, 11131, 11223, 11315, 11407, 11500, 11592, 11685, 11779, 11872,
-    11966, 12060, 12154, 12248, 12343, 12438, 12533, 12628, 12723, 12818, 12914, 13010, 13106,
-    13202, 13298, 13394, 13491, 13587, 13684, 13781, 13878, 13975, 14072, 14169, 14266, 14364,
-    14461, 14558, 14656, 14754, 14851, 14949, 15046, 15144, 15242, 15339, 15437, 15535, 15632,
-    15730, 15828, 15925, 16023, 16120, 16218, 16315, 16412, 16510, 16607, 16704, 16801, 16898,
-    16995, 17091, 17188, 17284, 17380, 17477, 17572, 17668, 17764, 17859, 17955, 18050, 18145,
-    18239, 18334, 18428, 18522, 18616, 18710, 18803, 18896, 18989, 19082, 19174, 19266, 19358,
-    19449, 19540, 19631, 19722, 19812, 19902, 19991, 20081, 20169, 20258, 20346, 20434, 20521,
-    20608, 20695, 20781, 20867, 20952, 21037, 21122, 21206, 21290, 21373, 21456, 21538, 21620,
-    21701, 21782, 21863, 21943, 22022, 22101, 22179, 22257, 22335, 22412, 22488, 22564, 22639,
-    22714, 22788, 22861, 22934, 23007, 23079, 23150, 23220, 23290, 23360, 23429, 23497, 23564,
-    23631, 23698, 23763, 23828, 23892, 23956, 24019, 24081, 24143, 24204, 24264, 24324, 24383,
-    24441, 24499, 24555, 24611, 24667, 24721, 24775, 24828, 24881, 24933, 24983, 25034, 25083,
-    25132, 25180, 25227, 25273, 25319, 25363, 25407, 25451, 25493, 25535, 25575, 25615, 25655,
-    25693, 25731, 25767, 25803, 25838, 25873, 25906, 25939, 25971, 26002, 26032, 26061, 26089,
-    26117, 26144, 26170, 26195, 26219, 26242, 26264, 26286, 26307, 26327, 26346, 26364, 26381,
-    26397, 26413, 26427, 26441, 26454, 26466, 26477, 26487, 26496, 26505, 26512, 26519, 26525,
-    26530, 26534, 26537, 26539, 26540, 26541, 26540, 26539, 26537, 26534, 26530, 26525, 26519,
-    26512, 26505, 26496, 26487, 26477, 26466, 26454, 26441, 26427, 26413, 26397, 26381, 26364,
-    26346, 26327, 26307, 26286, 26264, 26242, 26219, 26195, 26170, 26144, 26117, 26089, 26061,
-    26032, 26002, 25971, 25939, 25906, 25873, 25838, 25803, 25767, 25731, 25693, 25655, 25615,
-    25575, 25535, 25493, 25451, 25407, 25363, 25319, 25273, 25227, 25180, 25132, 25083, 25034,
-    24983, 24933, 24881, 24828, 24775, 24721, 24667, 24611, 24555, 24499, 24441, 24383, 24324,
-    24264, 24204, 24143, 24081, 24019, 23956, 23892, 23828, 23763, 23698, 23631, 23564, 23497,
-    23429, 23360, 23290, 23220, 23150, 23079, 23007, 22934, 22861, 22788, 22714, 22639, 22564,
-    22488, 22412, 22335, 22257, 22179, 22101, 22022, 21943, 21863, 21782, 21701, 21620, 21538,
-    21456, 21373, 21290, 21206, 21122, 21037, 20952, 20867, 20781, 20695, 20608, 20521, 20434,
-    20346, 20258, 20169, 20081, 19991, 19902, 19812, 19722, 19631, 19540, 19449, 19358, 19266,
-    19174, 19082, 18989, 18896, 18803, 18710, 18616, 18522, 18428, 18334, 18239, 18145, 18050,
-    17955, 17859, 17764, 17668, 17572, 17477, 17380, 17284, 17188, 17091, 16995, 16898, 16801,
-    16704, 16607, 16510, 16412, 16315, 16218, 16120, 16023, 15925, 15828, 15730, 15632, 15535,
-    15437, 15339, 15242, 15144, 15046, 14949, 14851, 14754, 14656, 14558, 14461, 14364, 14266,
-    14169, 14072, 13975, 13878, 13781, 13684, 13587, 13491, 13394, 13298, 13202, 13106, 13010,
-    12914, 12818, 12723, 12628, 12533, 12438, 12343, 12248, 12154, 12060, 11966, 11872, 11779,
-    11685, 11592, 11500, 11407, 11315, 11223, 11131, 11039, 10948, 10857, 10766, 10675, 10585,
-    10495, 10406, 10316, 10227, 10139, 10050, 9962, 9874, 9787, 9700, 9613, 9526, 9440, 9354, 9269,
-    9184, 9099, 9015, 8931, 8847, 8764, 8681, 8598, 8516, 8434, 8353, 8272, 8191, 8111, 8031, 7952,
-    7873, 7794, 7716, 7638, 7561, 7484, 7407, 7331, 7255, 7180, 7105, 7031, 6957, 6883, 6810, 6738,
-    6665, 6594, 6522, 6451, 6381, 6311, 6241, 6172, 6104, 6036, 5968, 5901, 5834, 5767, 5702, 5636,
-    5571, 5507, 5443, 5379, 5316, 5253, 5191, 5130, 5068, 5008, 4947, 4888, 4828, 4769, 4711, 4653,
-    4596, 4539, 4482, 4426, 4371, 4316, 4261, 4207, 4153, 4100, 4047, 3995, 3943, 3892, 3841, 3791,
-    3741, 3691, 3642, 3594, 3546, 3498, 3451, 3404, 3358, 3312, 3267, 3222, 3178, 3134, 3090, 3047,
-    3005, 2962, 2921, 2879, 2839, 2798, 2758, 2719, 2680, 2641, 2603, 2565, 2528, 2491, 2454, 2418,
-    2382, 2347, 2312, 2278, 2244, 2210, 2177, 2144, 2112, 2080, 2048, 2017, 1986, 1956, 1926, 1896,
-    1867, 1838, 1810, 1781, 1754, 1726, 1699, 1673, 1646, 1620, 1595, 1570, 1545, 1520, 1496, 1472,
-    1449, 1426, 1403, 1380, 1358, 1336, 1315, 1294, 1273, 1252, 1232, 1212, 1192, 1173, 1154, 1135,
-    1117, 1099, 1081, 1063, 1046, 1029, 1012, 996, 980, 964, 948, 933, 918, 903, 888, 874, 860,
-    846, 833, 819, 806, 793, 781, 768, 756, 744, 733, 721, 710, 699, 688, 677, 667, 657, 647, 637,
-    627, 618, 609, 599, 591, 582, 574, 565, 557, 549, 541, 534, 526, 519, 512, 505, 498, 492, 485,
-    479, 473, 467, 461, 455, 450, 444, 439, 434, 429, 424, 419, 415, 410, 406, 402, 398, 394, 390,
-    386, 383, 379, 376, 373, 370, 367, 364, 361, 359, 356, 354, 351, 349, 347, 345, 343, 342, 340,
-    338, 337, 336, 334, 333, 332, 331, 330, 330, 329, 328, 328, 328, 327, 327, 327, 327, 327, 328,
-    328, 328, 329, 330, 330, 331, 332, 333, 334, 336, 337, 338, 340, 342, 343, 345, 347, 349, 351,
-    354, 356, 359, 361, 364, 367, 370, 373, 376, 379, 383, 386, 390, 394, 398, 402, 406, 410, 415,
-    419, 424, 429, 434, 439, 444, 450, 455, 461, 467, 473, 479, 485, 492, 498, 505, 512, 519, 526,
-    534, 541, 549, 557, 565, 574, 582, 591, 599, 609, 618, 627, 637, 647, 657, 667, 677, 688, 699,
-    710, 721, 733, 744, 756, 768, 781, 793, 806, 819, 833, 846, 860, 874, 888, 903, 918, 933, 948,
-    964, 980, 996, 1012, 1029, 1046, 1063, 1081, 1099, 1117, 1135, 1154, 1173, 1192, 1212, 1232,
-    1252, 1273, 1294, 1315, 1336, 1358, 1380, 1403, 1426, 1449, 1472, 1496, 1520, 1545, 1570, 1595,
-    1620, 1646, 1673, 1699, 1726, 1754, 1781, 1810, 1838, 1867, 1896, 1926, 1956, 1986, 2017, 2048,
-    2080, 2112, 2144, 2177, 2210, 2244, 2278, 2312, 2347, 2382, 2418, 2454, 2491, 2528, 2565, 2603,
-    2641, 2680, 2719, 2758, 2798, 2839, 2879, 2921, 2962, 3005, 3047, 3090, 3134, 3178, 3222, 3267,
-    3312, 3358, 3404, 3451, 3498, 3546, 3594, 3642, 3691, 3741, 3791, 3841, 3892, 3943, 3995, 4047,
-    4100, 4153, 4207, 4261, 4316, 4371, 4426, 4482, 4539, 4596, 4653, 4711, 4769, 4828, 4888, 4947,
-    5008, 5068, 5130, 5191, 5253, 5316, 5379, 5443, 5507, 5571, 5636, 5702, 5767, 5834, 5901, 5968,
-    6036, 6104, 6172, 6241, 6311, 6381, 6451, 6522, 6594, 6665, 6738, 6810, 6883, 6957, 7031, 7105,
-    7180, 7255, 7331, 7407, 7484, 7561, 7638, 7716, 7794, 7873, 7952, 8031, 8111,
-];
-
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = Pwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
-    pwm.set_prescaler(Prescaler::Div1);
+    let pwm = Pwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
+    // sg90 microervo requires 50hz or 20ms period
+    // set_period can only set down to 125khz so we cant use it directly
+    // Div128 is 125khz or 0.000008s or 0.008ms, 20/0.008 is 2500 is top
+    pwm.set_prescaler(Prescaler::Div128);
+    pwm.set_max_duty(2500);
     info!("pwm initialized!");
 
-    let mut i = 0;
+    Timer::after(Duration::from_millis(5000)).await;
+
+    // 1ms 0deg (1/.008=125), 1.5ms 90deg (1.5/.008=187.5), 2ms 180deg (2/.008=250),
     loop {
-        i += 1;
-        pwm.set_duty(0, DUTY[i % 1024]);
-        pwm.set_duty(1, DUTY[(i + 256) % 1024]);
-        pwm.set_duty(2, DUTY[(i + 512) % 1024]);
-        pwm.set_duty(3, DUTY[(i + 768) % 1024]);
-        Timer::after(Duration::from_millis(3)).await;
+        info!("45 deg");
+        pwm.set_duty(0, 2500 - 156);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("90 deg");
+        pwm.set_duty(0, 2500 - 187);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("135 deg");
+        pwm.set_duty(0, 2500 - 218);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("180 deg");
+        pwm.set_duty(0, 2500 - 250);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("0 deg");
+        pwm.set_duty(0, 2500 - 125);
+        Timer::after(Duration::from_millis(5000)).await;
     }
 }

From f2cfbe42629c74fd53f709ad7187d00b21d7030a Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 13:00:50 -0700
Subject: [PATCH 17/47] align pwm.set_duty with embedded hal to not be one shot

---
 embassy-nrf/src/pwm.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 31e8a3b6..3594e6af 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -282,8 +282,15 @@ impl<'d, T: Instance> Pwm<'d, T> {
         let s = T::state();
         unsafe { (*s.duty.get())[channel] = duty & 0x7FFF };
 
+        // todo justify? should i fence elsehwere we task start? or
         compiler_fence(Ordering::SeqCst);
-        T::regs().tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
+
+        // play duty cycle infinitely
+        let r = T::regs();
+        r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
+        r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
+        // tasks_seqstart doesnt exist in all svds so write its bit instead
+        r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
     }
 
     /// Sets the PWM clock prescaler.

From 74e7f4a22717a73f735caa97589c9603091016e6 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 13:16:24 -0700
Subject: [PATCH 18/47] comments

---
 embassy-nrf/src/pwm.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 3594e6af..947cd873 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -66,7 +66,7 @@ pub enum SequenceMode {
 pub struct SequenceConfig<'a> {
     /// Selects up mode or up-and-down mode for the counter
     pub counter_mode: CounterMode,
-    // Top value to be compared against buffer values
+    /// Top value to be compared against buffer values
     pub top: u16,
     /// Configuration for PWM_CLK
     pub prescaler: Prescaler,
@@ -170,7 +170,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         }
     }
 
-    /// Returns a configured pwm that has had start called on it
+    /// Play a `SequenceConfig` sequence instead of a stable `set_duty` output
     pub fn play_sequence(&self, config: SequenceConfig) -> Result<(), Error> {
         slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
 
@@ -233,6 +233,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
                 r.loop_.write(|w| unsafe { w.cnt().bits(times) });
 
+                // we can subtract 1 by starting at seq1 instead of seq0
                 if odd {
                     // tasks_seqstart doesnt exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });

From b297e5f7bd152d1e5147631c81987c26f9fa0664 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 13:51:40 -0700
Subject: [PATCH 19/47] led dimming example, dont need to keep all examples,
 just covering ground to test api

---
 examples/nrf/src/bin/pwm_led.rs | 47 +++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 examples/nrf/src/bin/pwm_led.rs

diff --git a/examples/nrf/src/bin/pwm_led.rs b/examples/nrf/src/bin/pwm_led.rs
new file mode 100644
index 00000000..067f4d2c
--- /dev/null
+++ b/examples/nrf/src/bin/pwm_led.rs
@@ -0,0 +1,47 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::gpio::NoPin;
+use embassy_nrf::pwm::{Prescaler, Pwm};
+use embassy_nrf::Peripherals;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let pwm = Pwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
+    // set_period doesnt actually set what you give it, because it only has a
+    // few options from the hardhware so be explicit instead
+    // Div128 is slowest, 125khz still crazy fast for our eyes
+    pwm.set_prescaler(Prescaler::Div128);
+
+    info!("pwm initialized!");
+
+    // default max_duty if not specified is 1000
+    // so 0 would be fully off and 1000 or above would be fully on
+    loop {
+        info!("100%");
+        pwm.set_duty(0, 1000);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("25%");
+        pwm.set_duty(0, 250);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("10%");
+        pwm.set_duty(0, 100);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("5%");
+        pwm.set_duty(0, 50);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("0%");
+        pwm.set_duty(0, 0);
+        Timer::after(Duration::from_millis(5000)).await;
+    }
+}

From 49253152cff2a45bd08cd1801bb6d5f0f3ce9b30 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 19:11:37 -0700
Subject: [PATCH 20/47] seperate sequence from duty cycle pwm struct

---
 embassy-nrf/src/pwm.rs                 | 260 +++++++++++++++++--------
 examples/nrf/src/bin/pwm_sequence.rs   |   9 +-
 examples/nrf/src/bin/pwm_simple_sin.rs |   9 +-
 3 files changed, 186 insertions(+), 92 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 947cd873..a59fddf7 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -54,6 +54,176 @@ pub struct Pwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
+pub struct PwmSeq<'d, T: Instance> {
+    phantom: PhantomData<&'d mut T>,
+}
+
+impl<'d, T: Instance> PwmSeq<'d, T> {
+    /// Creates the interface to a PWM instance.
+    ///
+    /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
+    ///
+    /// # Safety
+    ///
+    /// The returned API is safe unless you use `mem::forget` (or similar safe
+    /// mechanisms) on stack allocated buffers which which have been passed to
+    /// [`send()`](Pwm::send) or [`receive`](Pwm::receive).
+    #[allow(unused_unsafe)]
+    pub fn new(
+        _pwm: impl Unborrow<Target = T> + 'd,
+        ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch1: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch2: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        ch3: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
+        config: SequenceConfig,
+    ) -> Result<Self, Error> {
+        slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
+
+        if config.sequence.len() > 32767 {
+            return Err(Error::SequenceTooLong);
+        }
+        if let SequenceMode::Times(0) = config.times {
+            return Err(Error::SequenceTooShort);
+        }
+
+        unborrow!(ch0, ch1, ch2, ch3);
+
+        let r = T::regs();
+
+        if let Some(pin) = ch0.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+        }
+        if let Some(pin) = ch1.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+        }
+        if let Some(pin) = ch2.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+        }
+        if let Some(pin) = ch3.pin_mut() {
+            pin.set_low();
+            pin.conf().write(|w| w.dir().output());
+        }
+
+        // if NoPin provided writes disconnected (top bit 1) 0x80000000 else
+        // writes pin number ex 13 (0x0D) which is connected (top bit 0)
+        r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
+        r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
+        r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
+        r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
+
+        // Disable all interrupts
+        r.intenset.reset();
+        r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
+        r.shorts.reset();
+
+        // Enable
+        r.enable.write(|w| w.enable().enabled());
+        r.mode
+            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
+        r.prescaler
+            .write(|w| w.prescaler().bits(config.prescaler as u8));
+        r.countertop
+            .write(|w| unsafe { w.countertop().bits(config.top) });
+
+        r.decoder.write(|w| {
+            w.load().bits(config.sequence_load as u8);
+            w.mode().refresh_count()
+        });
+
+        r.seq0
+            .ptr
+            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+        r.seq0
+            .cnt
+            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+        r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
+        r.seq0
+            .enddelay
+            .write(|w| unsafe { w.bits(config.end_delay) });
+
+        r.seq1
+            .ptr
+            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+        r.seq1
+            .cnt
+            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+        r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
+        r.seq1
+            .enddelay
+            .write(|w| unsafe { w.bits(config.end_delay) });
+
+        match config.times {
+            // just the one time, no loop count
+            SequenceMode::Times(1) => {
+                r.loop_.write(|w| w.cnt().disabled());
+                // tasks_seqstart doesnt exist in all svds so write its bit instead
+                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+            }
+            // loop count is how many times to play BOTH sequences
+            // 2 total  (1 x 2)
+            // 3 total, (2 x 2) - 1
+            SequenceMode::Times(n) => {
+                let odd = n & 1 == 1;
+                let times = if odd { (n / 2) + 1 } else { n / 2 };
+
+                r.loop_.write(|w| unsafe { w.cnt().bits(times) });
+
+                // we can subtract 1 by starting at seq1 instead of seq0
+                if odd {
+                    // tasks_seqstart doesnt exist in all svds so write its bit instead
+                    r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+                } else {
+                    // tasks_seqstart doesnt exist in all svds so write its bit instead
+                    r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+                }
+            }
+            // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
+            SequenceMode::Infinite => {
+                r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
+                r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
+                // tasks_seqstart doesnt exist in all svds so write its bit instead
+                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+            }
+        }
+
+        Ok(Self {
+            phantom: PhantomData,
+        })
+    }
+
+    /// Stop playback
+    #[inline(always)]
+    pub fn stop(&self) {
+        let r = T::regs();
+
+        r.shorts.reset();
+
+        // tasks_stop doesnt exist in all svds so write its bit instead
+        r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
+    }
+
+    /// Disables the PWM generator.
+    #[inline(always)]
+    pub fn disable(&self) {
+        let r = T::regs();
+        r.enable.write(|w| w.enable().disabled());
+    }
+}
+
+impl<'a, T: Instance> Drop for PwmSeq<'a, T> {
+    fn drop(&mut self) {
+        self.stop();
+        self.disable();
+
+        info!("pwm drop: done");
+
+        // TODO: disable pins
+    }
+}
+
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum SequenceMode {
     /// Run sequence n Times total
@@ -98,6 +268,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
     /// Creates the interface to a PWM instance.
     ///
     /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
+    /// Must be started by calling `set_duty`
     ///
     /// # Safety
     ///
@@ -170,92 +341,9 @@ impl<'d, T: Instance> Pwm<'d, T> {
         }
     }
 
-    /// Play a `SequenceConfig` sequence instead of a stable `set_duty` output
-    pub fn play_sequence(&self, config: SequenceConfig) -> Result<(), Error> {
-        slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
-
-        if config.sequence.len() > 32767 {
-            return Err(Error::SequenceTooLong);
-        }
-        if let SequenceMode::Times(0) = config.times {
-            return Err(Error::SequenceTooShort);
-        }
-
-        let r = T::regs();
-
-        r.mode
-            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
-        r.prescaler
-            .write(|w| w.prescaler().bits(config.prescaler as u8));
-        r.countertop
-            .write(|w| unsafe { w.countertop().bits(config.top) });
-
-        r.decoder.write(|w| {
-            w.load().bits(config.sequence_load as u8);
-            w.mode().refresh_count()
-        });
-
-        r.seq0
-            .ptr
-            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
-        r.seq0
-            .cnt
-            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
-        r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
-        r.seq0
-            .enddelay
-            .write(|w| unsafe { w.bits(config.end_delay) });
-
-        r.seq1
-            .ptr
-            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
-        r.seq1
-            .cnt
-            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
-        r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
-        r.seq1
-            .enddelay
-            .write(|w| unsafe { w.bits(config.end_delay) });
-
-        match config.times {
-            // just the one time, no loop count
-            SequenceMode::Times(1) => {
-                r.loop_.write(|w| w.cnt().disabled());
-                // tasks_seqstart doesnt exist in all svds so write its bit instead
-                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-            }
-            // loop count is how many times to play BOTH sequences
-            // 2 total  (1 x 2)
-            // 3 total, (2 x 2) - 1
-            SequenceMode::Times(n) => {
-                let odd = n & 1 == 1;
-                let times = if odd { (n / 2) + 1 } else { n / 2 };
-
-                r.loop_.write(|w| unsafe { w.cnt().bits(times) });
-
-                // we can subtract 1 by starting at seq1 instead of seq0
-                if odd {
-                    // tasks_seqstart doesnt exist in all svds so write its bit instead
-                    r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
-                } else {
-                    // tasks_seqstart doesnt exist in all svds so write its bit instead
-                    r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-                }
-            }
-            // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
-            SequenceMode::Infinite => {
-                r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
-                r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
-                // tasks_seqstart doesnt exist in all svds so write its bit instead
-                r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-            }
-        }
-        Ok(())
-    }
-
     /// Stop playback
     #[inline(always)]
-    pub fn sequence_stop(&self) {
+    pub fn stop(&self) {
         let r = T::regs();
 
         r.shorts.reset();
@@ -264,6 +352,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
 
+    // todo should this do.. something useful
     /// Enables the PWM generator.
     #[inline(always)]
     pub fn enable(&self) {
@@ -271,6 +360,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.enable.write(|w| w.enable().enabled());
     }
 
+    // todo should this stop the task? or should you just use set_duty to 0?
     /// Disables the PWM generator.
     #[inline(always)]
     pub fn disable(&self) {
@@ -349,7 +439,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
 impl<'a, T: Instance> Drop for Pwm<'a, T> {
     fn drop(&mut self) {
-        self.sequence_stop();
+        self.stop();
         self.disable();
 
         info!("pwm drop: done");
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 066ab3c0..0a7bea1c 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,7 +7,9 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{CounterMode, Prescaler, Pwm, SequenceConfig, SequenceLoad, SequenceMode};
+use embassy_nrf::pwm::{
+    CounterMode, Prescaler, PwmSeq, SequenceConfig, SequenceLoad, SequenceMode,
+};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
@@ -27,8 +29,9 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         times: SequenceMode::Times(5),
     };
 
-    let pwm = Pwm::new(p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14);
-    unwrap!(pwm.play_sequence(config));
+    let _pwm = unwrap!(PwmSeq::new(
+        p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
+    ));
     info!("pwm started!");
 
     loop {
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 3c1bddbc..6fd59c6a 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -9,7 +9,9 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{CounterMode, Prescaler, Pwm, SequenceConfig, SequenceLoad, SequenceMode};
+use embassy_nrf::pwm::{
+    CounterMode, Prescaler, PwmSeq, SequenceConfig, SequenceLoad, SequenceMode,
+};
 use embassy_nrf::Peripherals;
 use micromath::F32Ext;
 
@@ -31,13 +33,12 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         times: SequenceMode::Infinite,
     };
 
-    let pwm = Pwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
-    unwrap!(pwm.play_sequence(config));
+    let pwm = unwrap!(PwmSeq::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config));
     info!("pwm started!");
 
     Timer::after(Duration::from_millis(20000)).await;
 
-    pwm.sequence_stop();
+    pwm.stop();
     info!("pwm stopped!");
 
     loop {

From 4647792ad68209f3be6e1cdf1cee9513025c14ab Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Mon, 1 Nov 2021 20:18:24 -0700
Subject: [PATCH 21/47] seperate start from pwmseq::new

---
 embassy-nrf/src/pwm.rs                 | 37 +++++++++++++++++---------
 examples/nrf/src/bin/pwm_sequence.rs   |  4 +--
 examples/nrf/src/bin/pwm_simple_sin.rs |  2 +-
 3 files changed, 28 insertions(+), 15 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index a59fddf7..9454ad4a 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -59,9 +59,9 @@ pub struct PwmSeq<'d, T: Instance> {
 }
 
 impl<'d, T: Instance> PwmSeq<'d, T> {
-    /// Creates the interface to a PWM instance.
+    /// Creates the interface to a PWM Sequence interface.
     ///
-    /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
+    /// Must be started by calling `start`
     ///
     /// # Safety
     ///
@@ -82,9 +82,6 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
         if config.sequence.len() > 32767 {
             return Err(Error::SequenceTooLong);
         }
-        if let SequenceMode::Times(0) = config.times {
-            return Err(Error::SequenceTooShort);
-        }
 
         unborrow!(ch0, ch1, ch2, ch3);
 
@@ -155,7 +152,27 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
             .enddelay
             .write(|w| unsafe { w.bits(config.end_delay) });
 
-        match config.times {
+        Ok(Self {
+            phantom: PhantomData,
+        })
+    }
+
+    /// Start or restart playback
+    #[inline(always)]
+    pub fn start(&self, times: SequenceMode) -> Result<(), Error> {
+        if let SequenceMode::Times(0) = times {
+            return Err(Error::SequenceNoZero);
+        }
+        let r = T::regs();
+
+        r.shorts.reset();
+
+        // tasks_stop doesnt exist in all svds so write its bit instead
+        r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
+
+        r.enable.write(|w| w.enable().enabled());
+
+        match times {
             // just the one time, no loop count
             SequenceMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
@@ -189,9 +206,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
             }
         }
 
-        Ok(Self {
-            phantom: PhantomData,
-        })
+        Ok(())
     }
 
     /// Stop playback
@@ -248,8 +263,6 @@ pub struct SequenceConfig<'a> {
     pub refresh: u32,
     /// Number of Times PWM periods after the sequence ends before starting the next sequence
     pub end_delay: u32,
-    /// How many times to play the sequence
-    pub times: SequenceMode,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -259,7 +272,7 @@ pub enum Error {
     /// Max Sequence size is 32767
     SequenceTooLong,
     /// Min Sequence size is 1
-    SequenceTooShort,
+    SequenceNoZero,
     /// EasyDMA can only read from data memory, read only buffers in flash will fail.
     DMABufferNotInDataMemory,
 }
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 0a7bea1c..6911d034 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -26,12 +26,12 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence_load: SequenceLoad::Individual,
         refresh: 0,
         end_delay: 0,
-        times: SequenceMode::Times(5),
     };
 
-    let _pwm = unwrap!(PwmSeq::new(
+    let pwm = unwrap!(PwmSeq::new(
         p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
     ));
+    unwrap!(pwm.start(SequenceMode::Times(5)));
     info!("pwm started!");
 
     loop {
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 6fd59c6a..985f9d80 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -30,10 +30,10 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         sequence_load: SequenceLoad::Common,
         refresh: 0,
         end_delay: 0,
-        times: SequenceMode::Infinite,
     };
 
     let pwm = unwrap!(PwmSeq::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config));
+    unwrap!(pwm.start(SequenceMode::Infinite));
     info!("pwm started!");
 
     Timer::after(Duration::from_millis(20000)).await;

From c939edb8d03a6ddf965507e3b2de02b82ca255b4 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Tue, 2 Nov 2021 10:57:01 -0700
Subject: [PATCH 22/47] rename error enum again

---
 embassy-nrf/src/pwm.rs                 | 4 ++--
 examples/nrf/src/bin/pwm_sequence.rs   | 2 +-
 examples/nrf/src/bin/pwm_simple_sin.rs | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 9454ad4a..6468f267 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -161,7 +161,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
     #[inline(always)]
     pub fn start(&self, times: SequenceMode) -> Result<(), Error> {
         if let SequenceMode::Times(0) = times {
-            return Err(Error::SequenceNoZero);
+            return Err(Error::SequenceTimesAtLeastOne);
         }
         let r = T::regs();
 
@@ -272,7 +272,7 @@ pub enum Error {
     /// Max Sequence size is 32767
     SequenceTooLong,
     /// Min Sequence size is 1
-    SequenceNoZero,
+    SequenceTimesAtLeastOne,
     /// EasyDMA can only read from data memory, read only buffers in flash will fail.
     DMABufferNotInDataMemory,
 }
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 6911d034..8830e52d 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -31,7 +31,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     let pwm = unwrap!(PwmSeq::new(
         p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
     ));
-    unwrap!(pwm.start(SequenceMode::Times(5)));
+    let _ = pwm.start(SequenceMode::Times(5));
     info!("pwm started!");
 
     loop {
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index 985f9d80..ac3089c8 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -33,7 +33,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     };
 
     let pwm = unwrap!(PwmSeq::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config));
-    unwrap!(pwm.start(SequenceMode::Infinite));
+    let _ = pwm.start(SequenceMode::Infinite);
     info!("pwm started!");
 
     Timer::after(Duration::from_millis(20000)).await;

From 682274870f89f1a3585d3df497886d2bca9b1f88 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Tue, 2 Nov 2021 11:56:01 -0700
Subject: [PATCH 23/47] set_duty does indeed loop forever

---
 embassy-nrf/src/pwm.rs | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 6468f267..760f36a5 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -165,18 +165,16 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
         }
         let r = T::regs();
 
-        r.shorts.reset();
-
-        // tasks_stop doesnt exist in all svds so write its bit instead
-        r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
+        self.stop();
 
         r.enable.write(|w| w.enable().enabled());
 
         match times {
+            // todo why doesn't this play forever? set_duty does...
             // just the one time, no loop count
             SequenceMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
-                // tasks_seqstart doesnt exist in all svds so write its bit instead
+                // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
             // loop count is how many times to play BOTH sequences
@@ -190,10 +188,10 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
 
                 // we can subtract 1 by starting at seq1 instead of seq0
                 if odd {
-                    // tasks_seqstart doesnt exist in all svds so write its bit instead
+                    // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
                 } else {
-                    // tasks_seqstart doesnt exist in all svds so write its bit instead
+                    // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
                 }
             }
@@ -201,7 +199,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
             SequenceMode::Infinite => {
                 r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
                 r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
-                // tasks_seqstart doesnt exist in all svds so write its bit instead
+                // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
             }
         }
@@ -216,7 +214,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
 
         r.shorts.reset();
 
-        // tasks_stop doesnt exist in all svds so write its bit instead
+        // tasks_stop() doesn't exist in all svds so write its bit instead
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
 
@@ -361,7 +359,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
         r.shorts.reset();
 
-        // tasks_stop doesnt exist in all svds so write its bit instead
+        // tasks_stop() doesn't exist in all svds so write its bit instead
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
 
@@ -383,17 +381,15 @@ impl<'d, T: Instance> Pwm<'d, T> {
 
     /// Sets duty cycle (15 bit) for a PWM channel.
     pub fn set_duty(&self, channel: usize, duty: u16) {
+        let r = T::regs();
         let s = T::state();
         unsafe { (*s.duty.get())[channel] = duty & 0x7FFF };
 
         // todo justify? should i fence elsehwere we task start? or
         compiler_fence(Ordering::SeqCst);
 
-        // play duty cycle infinitely
-        let r = T::regs();
-        r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
-        r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
-        // tasks_seqstart doesnt exist in all svds so write its bit instead
+        // todo why does this play forever when times(1) doesn't?
+        // tasks_seqstart() doesn't exist in all svds so write its bit instead
         r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
     }
 

From 44375b427c20273d91845e5e012e669d8a2e1cc0 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 15:26:44 -0700
Subject: [PATCH 24/47] restore example and add set_time_stretch api

---
 embassy-nrf/src/pwm.rs            |   6 ++
 examples/nrf/src/bin/pwm.rs       | 113 ++++++++++++++++++++++--------
 examples/nrf/src/bin/pwm_servo.rs |  48 +++++++++++++
 3 files changed, 138 insertions(+), 29 deletions(-)
 create mode 100644 examples/nrf/src/bin/pwm_servo.rs

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 760f36a5..8c26adac 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -423,6 +423,12 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .write(|w| unsafe { w.countertop().bits(duty.min(32767u16)) });
     }
 
+    /// Additional number of PWM periods spent on each duty cycle value.
+    #[inline(always)]
+    pub fn set_time_stretch(&self, refresh: u32) {
+        T::regs().seq0.refresh.write(|w| unsafe { w.bits(refresh) });
+    }
+
     /// Returns the maximum duty cycle value.
     #[inline(always)]
     pub fn max_duty(&self) -> u16 {
diff --git a/examples/nrf/src/bin/pwm.rs b/examples/nrf/src/bin/pwm.rs
index aeda80be..4c18b77b 100644
--- a/examples/nrf/src/bin/pwm.rs
+++ b/examples/nrf/src/bin/pwm.rs
@@ -7,42 +7,97 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::gpio::NoPin;
 use embassy_nrf::pwm::{Prescaler, Pwm};
 use embassy_nrf::Peripherals;
 
+// for i in range(1024): print(int((math.sin(i/512*math.pi)*0.4+0.5)**2*32767), ', ', end='')
+static DUTY: [u16; 1024] = [
+    8191, 8272, 8353, 8434, 8516, 8598, 8681, 8764, 8847, 8931, 9015, 9099, 9184, 9269, 9354, 9440,
+    9526, 9613, 9700, 9787, 9874, 9962, 10050, 10139, 10227, 10316, 10406, 10495, 10585, 10675,
+    10766, 10857, 10948, 11039, 11131, 11223, 11315, 11407, 11500, 11592, 11685, 11779, 11872,
+    11966, 12060, 12154, 12248, 12343, 12438, 12533, 12628, 12723, 12818, 12914, 13010, 13106,
+    13202, 13298, 13394, 13491, 13587, 13684, 13781, 13878, 13975, 14072, 14169, 14266, 14364,
+    14461, 14558, 14656, 14754, 14851, 14949, 15046, 15144, 15242, 15339, 15437, 15535, 15632,
+    15730, 15828, 15925, 16023, 16120, 16218, 16315, 16412, 16510, 16607, 16704, 16801, 16898,
+    16995, 17091, 17188, 17284, 17380, 17477, 17572, 17668, 17764, 17859, 17955, 18050, 18145,
+    18239, 18334, 18428, 18522, 18616, 18710, 18803, 18896, 18989, 19082, 19174, 19266, 19358,
+    19449, 19540, 19631, 19722, 19812, 19902, 19991, 20081, 20169, 20258, 20346, 20434, 20521,
+    20608, 20695, 20781, 20867, 20952, 21037, 21122, 21206, 21290, 21373, 21456, 21538, 21620,
+    21701, 21782, 21863, 21943, 22022, 22101, 22179, 22257, 22335, 22412, 22488, 22564, 22639,
+    22714, 22788, 22861, 22934, 23007, 23079, 23150, 23220, 23290, 23360, 23429, 23497, 23564,
+    23631, 23698, 23763, 23828, 23892, 23956, 24019, 24081, 24143, 24204, 24264, 24324, 24383,
+    24441, 24499, 24555, 24611, 24667, 24721, 24775, 24828, 24881, 24933, 24983, 25034, 25083,
+    25132, 25180, 25227, 25273, 25319, 25363, 25407, 25451, 25493, 25535, 25575, 25615, 25655,
+    25693, 25731, 25767, 25803, 25838, 25873, 25906, 25939, 25971, 26002, 26032, 26061, 26089,
+    26117, 26144, 26170, 26195, 26219, 26242, 26264, 26286, 26307, 26327, 26346, 26364, 26381,
+    26397, 26413, 26427, 26441, 26454, 26466, 26477, 26487, 26496, 26505, 26512, 26519, 26525,
+    26530, 26534, 26537, 26539, 26540, 26541, 26540, 26539, 26537, 26534, 26530, 26525, 26519,
+    26512, 26505, 26496, 26487, 26477, 26466, 26454, 26441, 26427, 26413, 26397, 26381, 26364,
+    26346, 26327, 26307, 26286, 26264, 26242, 26219, 26195, 26170, 26144, 26117, 26089, 26061,
+    26032, 26002, 25971, 25939, 25906, 25873, 25838, 25803, 25767, 25731, 25693, 25655, 25615,
+    25575, 25535, 25493, 25451, 25407, 25363, 25319, 25273, 25227, 25180, 25132, 25083, 25034,
+    24983, 24933, 24881, 24828, 24775, 24721, 24667, 24611, 24555, 24499, 24441, 24383, 24324,
+    24264, 24204, 24143, 24081, 24019, 23956, 23892, 23828, 23763, 23698, 23631, 23564, 23497,
+    23429, 23360, 23290, 23220, 23150, 23079, 23007, 22934, 22861, 22788, 22714, 22639, 22564,
+    22488, 22412, 22335, 22257, 22179, 22101, 22022, 21943, 21863, 21782, 21701, 21620, 21538,
+    21456, 21373, 21290, 21206, 21122, 21037, 20952, 20867, 20781, 20695, 20608, 20521, 20434,
+    20346, 20258, 20169, 20081, 19991, 19902, 19812, 19722, 19631, 19540, 19449, 19358, 19266,
+    19174, 19082, 18989, 18896, 18803, 18710, 18616, 18522, 18428, 18334, 18239, 18145, 18050,
+    17955, 17859, 17764, 17668, 17572, 17477, 17380, 17284, 17188, 17091, 16995, 16898, 16801,
+    16704, 16607, 16510, 16412, 16315, 16218, 16120, 16023, 15925, 15828, 15730, 15632, 15535,
+    15437, 15339, 15242, 15144, 15046, 14949, 14851, 14754, 14656, 14558, 14461, 14364, 14266,
+    14169, 14072, 13975, 13878, 13781, 13684, 13587, 13491, 13394, 13298, 13202, 13106, 13010,
+    12914, 12818, 12723, 12628, 12533, 12438, 12343, 12248, 12154, 12060, 11966, 11872, 11779,
+    11685, 11592, 11500, 11407, 11315, 11223, 11131, 11039, 10948, 10857, 10766, 10675, 10585,
+    10495, 10406, 10316, 10227, 10139, 10050, 9962, 9874, 9787, 9700, 9613, 9526, 9440, 9354, 9269,
+    9184, 9099, 9015, 8931, 8847, 8764, 8681, 8598, 8516, 8434, 8353, 8272, 8191, 8111, 8031, 7952,
+    7873, 7794, 7716, 7638, 7561, 7484, 7407, 7331, 7255, 7180, 7105, 7031, 6957, 6883, 6810, 6738,
+    6665, 6594, 6522, 6451, 6381, 6311, 6241, 6172, 6104, 6036, 5968, 5901, 5834, 5767, 5702, 5636,
+    5571, 5507, 5443, 5379, 5316, 5253, 5191, 5130, 5068, 5008, 4947, 4888, 4828, 4769, 4711, 4653,
+    4596, 4539, 4482, 4426, 4371, 4316, 4261, 4207, 4153, 4100, 4047, 3995, 3943, 3892, 3841, 3791,
+    3741, 3691, 3642, 3594, 3546, 3498, 3451, 3404, 3358, 3312, 3267, 3222, 3178, 3134, 3090, 3047,
+    3005, 2962, 2921, 2879, 2839, 2798, 2758, 2719, 2680, 2641, 2603, 2565, 2528, 2491, 2454, 2418,
+    2382, 2347, 2312, 2278, 2244, 2210, 2177, 2144, 2112, 2080, 2048, 2017, 1986, 1956, 1926, 1896,
+    1867, 1838, 1810, 1781, 1754, 1726, 1699, 1673, 1646, 1620, 1595, 1570, 1545, 1520, 1496, 1472,
+    1449, 1426, 1403, 1380, 1358, 1336, 1315, 1294, 1273, 1252, 1232, 1212, 1192, 1173, 1154, 1135,
+    1117, 1099, 1081, 1063, 1046, 1029, 1012, 996, 980, 964, 948, 933, 918, 903, 888, 874, 860,
+    846, 833, 819, 806, 793, 781, 768, 756, 744, 733, 721, 710, 699, 688, 677, 667, 657, 647, 637,
+    627, 618, 609, 599, 591, 582, 574, 565, 557, 549, 541, 534, 526, 519, 512, 505, 498, 492, 485,
+    479, 473, 467, 461, 455, 450, 444, 439, 434, 429, 424, 419, 415, 410, 406, 402, 398, 394, 390,
+    386, 383, 379, 376, 373, 370, 367, 364, 361, 359, 356, 354, 351, 349, 347, 345, 343, 342, 340,
+    338, 337, 336, 334, 333, 332, 331, 330, 330, 329, 328, 328, 328, 327, 327, 327, 327, 327, 328,
+    328, 328, 329, 330, 330, 331, 332, 333, 334, 336, 337, 338, 340, 342, 343, 345, 347, 349, 351,
+    354, 356, 359, 361, 364, 367, 370, 373, 376, 379, 383, 386, 390, 394, 398, 402, 406, 410, 415,
+    419, 424, 429, 434, 439, 444, 450, 455, 461, 467, 473, 479, 485, 492, 498, 505, 512, 519, 526,
+    534, 541, 549, 557, 565, 574, 582, 591, 599, 609, 618, 627, 637, 647, 657, 667, 677, 688, 699,
+    710, 721, 733, 744, 756, 768, 781, 793, 806, 819, 833, 846, 860, 874, 888, 903, 918, 933, 948,
+    964, 980, 996, 1012, 1029, 1046, 1063, 1081, 1099, 1117, 1135, 1154, 1173, 1192, 1212, 1232,
+    1252, 1273, 1294, 1315, 1336, 1358, 1380, 1403, 1426, 1449, 1472, 1496, 1520, 1545, 1570, 1595,
+    1620, 1646, 1673, 1699, 1726, 1754, 1781, 1810, 1838, 1867, 1896, 1926, 1956, 1986, 2017, 2048,
+    2080, 2112, 2144, 2177, 2210, 2244, 2278, 2312, 2347, 2382, 2418, 2454, 2491, 2528, 2565, 2603,
+    2641, 2680, 2719, 2758, 2798, 2839, 2879, 2921, 2962, 3005, 3047, 3090, 3134, 3178, 3222, 3267,
+    3312, 3358, 3404, 3451, 3498, 3546, 3594, 3642, 3691, 3741, 3791, 3841, 3892, 3943, 3995, 4047,
+    4100, 4153, 4207, 4261, 4316, 4371, 4426, 4482, 4539, 4596, 4653, 4711, 4769, 4828, 4888, 4947,
+    5008, 5068, 5130, 5191, 5253, 5316, 5379, 5443, 5507, 5571, 5636, 5702, 5767, 5834, 5901, 5968,
+    6036, 6104, 6172, 6241, 6311, 6381, 6451, 6522, 6594, 6665, 6738, 6810, 6883, 6957, 7031, 7105,
+    7180, 7255, 7331, 7407, 7484, 7561, 7638, 7716, 7794, 7873, 7952, 8031, 8111,
+];
+
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = Pwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
-    // sg90 microervo requires 50hz or 20ms period
-    // set_period can only set down to 125khz so we cant use it directly
-    // Div128 is 125khz or 0.000008s or 0.008ms, 20/0.008 is 2500 is top
-    pwm.set_prescaler(Prescaler::Div128);
-    pwm.set_max_duty(2500);
+    let pwm = Pwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
+    pwm.set_prescaler(Prescaler::Div1);
+    pwm.set_max_duty(32767);
+    pwm.set_time_stretch(32);
     info!("pwm initialized!");
 
-    Timer::after(Duration::from_millis(5000)).await;
-
-    // 1ms 0deg (1/.008=125), 1.5ms 90deg (1.5/.008=187.5), 2ms 180deg (2/.008=250),
+    let mut i = 0;
     loop {
-        info!("45 deg");
-        pwm.set_duty(0, 2500 - 156);
-        Timer::after(Duration::from_millis(5000)).await;
-
-        info!("90 deg");
-        pwm.set_duty(0, 2500 - 187);
-        Timer::after(Duration::from_millis(5000)).await;
-
-        info!("135 deg");
-        pwm.set_duty(0, 2500 - 218);
-        Timer::after(Duration::from_millis(5000)).await;
-
-        info!("180 deg");
-        pwm.set_duty(0, 2500 - 250);
-        Timer::after(Duration::from_millis(5000)).await;
-
-        info!("0 deg");
-        pwm.set_duty(0, 2500 - 125);
-        Timer::after(Duration::from_millis(5000)).await;
+        i += 1;
+        pwm.set_duty(0, DUTY[i % 1024]);
+        pwm.set_duty(1, DUTY[(i + 256) % 1024]);
+        pwm.set_duty(2, DUTY[(i + 512) % 1024]);
+        pwm.set_duty(3, DUTY[(i + 768) % 1024]);
+        Timer::after(Duration::from_millis(3)).await;
     }
 }
diff --git a/examples/nrf/src/bin/pwm_servo.rs b/examples/nrf/src/bin/pwm_servo.rs
new file mode 100644
index 00000000..aeda80be
--- /dev/null
+++ b/examples/nrf/src/bin/pwm_servo.rs
@@ -0,0 +1,48 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy_nrf::gpio::NoPin;
+use embassy_nrf::pwm::{Prescaler, Pwm};
+use embassy_nrf::Peripherals;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let pwm = Pwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
+    // sg90 microervo requires 50hz or 20ms period
+    // set_period can only set down to 125khz so we cant use it directly
+    // Div128 is 125khz or 0.000008s or 0.008ms, 20/0.008 is 2500 is top
+    pwm.set_prescaler(Prescaler::Div128);
+    pwm.set_max_duty(2500);
+    info!("pwm initialized!");
+
+    Timer::after(Duration::from_millis(5000)).await;
+
+    // 1ms 0deg (1/.008=125), 1.5ms 90deg (1.5/.008=187.5), 2ms 180deg (2/.008=250),
+    loop {
+        info!("45 deg");
+        pwm.set_duty(0, 2500 - 156);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("90 deg");
+        pwm.set_duty(0, 2500 - 187);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("135 deg");
+        pwm.set_duty(0, 2500 - 218);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("180 deg");
+        pwm.set_duty(0, 2500 - 250);
+        Timer::after(Duration::from_millis(5000)).await;
+
+        info!("0 deg");
+        pwm.set_duty(0, 2500 - 125);
+        Timer::after(Duration::from_millis(5000)).await;
+    }
+}

From 82695c8f653cb1479ca00efaf4c2bcda65e49ff7 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:15:42 -0700
Subject: [PATCH 25/47] make both news configure registers in same order

---
 embassy-nrf/src/pwm.rs | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 8c26adac..4f60e30b 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -118,17 +118,6 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
 
         // Enable
         r.enable.write(|w| w.enable().enabled());
-        r.mode
-            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
-        r.prescaler
-            .write(|w| w.prescaler().bits(config.prescaler as u8));
-        r.countertop
-            .write(|w| unsafe { w.countertop().bits(config.top) });
-
-        r.decoder.write(|w| {
-            w.load().bits(config.sequence_load as u8);
-            w.mode().refresh_count()
-        });
 
         r.seq0
             .ptr
@@ -152,6 +141,18 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
             .enddelay
             .write(|w| unsafe { w.bits(config.end_delay) });
 
+        r.decoder.write(|w| {
+            w.load().bits(config.sequence_load as u8);
+            w.mode().refresh_count()
+        });
+
+        r.mode
+            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
+        r.prescaler
+            .write(|w| w.prescaler().bits(config.prescaler as u8));
+        r.countertop
+            .write(|w| unsafe { w.countertop().bits(config.top) });
+
         Ok(Self {
             phantom: PhantomData,
         })

From 511c5cb8927f1c55c4e006d03fa64fb0c00e154d Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:16:00 -0700
Subject: [PATCH 26/47] intenset in a noop

---
 embassy-nrf/src/pwm.rs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 4f60e30b..c054addf 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -112,7 +112,6 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
         r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
 
         // Disable all interrupts
-        r.intenset.reset();
         r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
         r.shorts.reset();
 
@@ -325,7 +324,6 @@ impl<'d, T: Instance> Pwm<'d, T> {
         r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
 
         // Disable all interrupts
-        r.intenset.reset();
         r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
         r.shorts.reset();
 

From 9a6c2de4ea473c06e1bb5731d51c9e9f64a6ba80 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:19:43 -0700
Subject: [PATCH 27/47] fix safety comments

---
 embassy-nrf/src/pwm.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index c054addf..ccf0e70a 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -67,7 +67,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
     ///
     /// The returned API is safe unless you use `mem::forget` (or similar safe
     /// mechanisms) on stack allocated buffers which which have been passed to
-    /// [`send()`](Pwm::send) or [`receive`](Pwm::receive).
+    /// [`new()`](PwmSeq::new).
     #[allow(unused_unsafe)]
     pub fn new(
         _pwm: impl Unborrow<Target = T> + 'd,
@@ -285,7 +285,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
     ///
     /// The returned API is safe unless you use `mem::forget` (or similar safe
     /// mechanisms) on stack allocated buffers which which have been passed to
-    /// [`send()`](Pwm::send) or [`receive`](Pwm::receive).
+    /// [`new()`](Pwm::new).
     #[allow(unused_unsafe)]
     pub fn new(
         _pwm: impl Unborrow<Target = T> + 'd,

From d961fd1015f7911dc1085035c37b0554b0184982 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:25:44 -0700
Subject: [PATCH 28/47] rename to SimplePwm and SequencePwm

---
 embassy-nrf/src/pwm.rs                 | 22 ++++++++--------------
 examples/nrf/src/bin/pwm.rs            |  5 ++---
 examples/nrf/src/bin/pwm_led.rs        |  4 ++--
 examples/nrf/src/bin/pwm_sequence.rs   |  4 ++--
 examples/nrf/src/bin/pwm_servo.rs      |  4 ++--
 examples/nrf/src/bin/pwm_simple_sin.rs |  6 ++++--
 6 files changed, 20 insertions(+), 25 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index ccf0e70a..0d06f845 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -50,15 +50,15 @@ pub enum CounterMode {
 }
 
 /// Interface to the PWM peripheral
-pub struct Pwm<'d, T: Instance> {
+pub struct SimplePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
-pub struct PwmSeq<'d, T: Instance> {
+pub struct SequencePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
-impl<'d, T: Instance> PwmSeq<'d, T> {
+impl<'d, T: Instance> SequencePwm<'d, T> {
     /// Creates the interface to a PWM Sequence interface.
     ///
     /// Must be started by calling `start`
@@ -67,7 +67,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
     ///
     /// The returned API is safe unless you use `mem::forget` (or similar safe
     /// mechanisms) on stack allocated buffers which which have been passed to
-    /// [`new()`](PwmSeq::new).
+    /// [`new()`](SequencePwm::new).
     #[allow(unused_unsafe)]
     pub fn new(
         _pwm: impl Unborrow<Target = T> + 'd,
@@ -226,7 +226,7 @@ impl<'d, T: Instance> PwmSeq<'d, T> {
     }
 }
 
-impl<'a, T: Instance> Drop for PwmSeq<'a, T> {
+impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
     fn drop(&mut self) {
         self.stop();
         self.disable();
@@ -275,7 +275,7 @@ pub enum Error {
     DMABufferNotInDataMemory,
 }
 
-impl<'d, T: Instance> Pwm<'d, T> {
+impl<'d, T: Instance> SimplePwm<'d, T> {
     /// Creates the interface to a PWM instance.
     ///
     /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
@@ -285,7 +285,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
     ///
     /// The returned API is safe unless you use `mem::forget` (or similar safe
     /// mechanisms) on stack allocated buffers which which have been passed to
-    /// [`new()`](Pwm::new).
+    /// [`new()`](SimplePwm::new).
     #[allow(unused_unsafe)]
     pub fn new(
         _pwm: impl Unborrow<Target = T> + 'd,
@@ -422,12 +422,6 @@ impl<'d, T: Instance> Pwm<'d, T> {
             .write(|w| unsafe { w.countertop().bits(duty.min(32767u16)) });
     }
 
-    /// Additional number of PWM periods spent on each duty cycle value.
-    #[inline(always)]
-    pub fn set_time_stretch(&self, refresh: u32) {
-        T::regs().seq0.refresh.write(|w| unsafe { w.bits(refresh) });
-    }
-
     /// Returns the maximum duty cycle value.
     #[inline(always)]
     pub fn max_duty(&self) -> u16 {
@@ -451,7 +445,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
     }
 }
 
-impl<'a, T: Instance> Drop for Pwm<'a, T> {
+impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
     fn drop(&mut self) {
         self.stop();
         self.disable();
diff --git a/examples/nrf/src/bin/pwm.rs b/examples/nrf/src/bin/pwm.rs
index 4c18b77b..0cb91cf1 100644
--- a/examples/nrf/src/bin/pwm.rs
+++ b/examples/nrf/src/bin/pwm.rs
@@ -7,7 +7,7 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{Prescaler, Pwm};
+use embassy_nrf::pwm::{Prescaler, SimplePwm};
 use embassy_nrf::Peripherals;
 
 // for i in range(1024): print(int((math.sin(i/512*math.pi)*0.4+0.5)**2*32767), ', ', end='')
@@ -85,10 +85,9 @@ static DUTY: [u16; 1024] = [
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = Pwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
+    let pwm = SimplePwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
     pwm.set_prescaler(Prescaler::Div1);
     pwm.set_max_duty(32767);
-    pwm.set_time_stretch(32);
     info!("pwm initialized!");
 
     let mut i = 0;
diff --git a/examples/nrf/src/bin/pwm_led.rs b/examples/nrf/src/bin/pwm_led.rs
index 067f4d2c..ced6a713 100644
--- a/examples/nrf/src/bin/pwm_led.rs
+++ b/examples/nrf/src/bin/pwm_led.rs
@@ -8,12 +8,12 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{Prescaler, Pwm};
+use embassy_nrf::pwm::{Prescaler, SimplePwm};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = Pwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
+    let pwm = SimplePwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
     // set_period doesnt actually set what you give it, because it only has a
     // few options from the hardhware so be explicit instead
     // Div128 is slowest, 125khz still crazy fast for our eyes
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 8830e52d..82575d70 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -8,7 +8,7 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::pwm::{
-    CounterMode, Prescaler, PwmSeq, SequenceConfig, SequenceLoad, SequenceMode,
+    CounterMode, Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm,
 };
 use embassy_nrf::Peripherals;
 
@@ -28,7 +28,7 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         end_delay: 0,
     };
 
-    let pwm = unwrap!(PwmSeq::new(
+    let pwm = unwrap!(SequencePwm::new(
         p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
     ));
     let _ = pwm.start(SequenceMode::Times(5));
diff --git a/examples/nrf/src/bin/pwm_servo.rs b/examples/nrf/src/bin/pwm_servo.rs
index aeda80be..d681a201 100644
--- a/examples/nrf/src/bin/pwm_servo.rs
+++ b/examples/nrf/src/bin/pwm_servo.rs
@@ -8,12 +8,12 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{Prescaler, Pwm};
+use embassy_nrf::pwm::{Prescaler, SimplePwm};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = Pwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
+    let pwm = SimplePwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
     // sg90 microervo requires 50hz or 20ms period
     // set_period can only set down to 125khz so we cant use it directly
     // Div128 is 125khz or 0.000008s or 0.008ms, 20/0.008 is 2500 is top
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index ac3089c8..afafb5d9 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -10,7 +10,7 @@ use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
 use embassy_nrf::pwm::{
-    CounterMode, Prescaler, PwmSeq, SequenceConfig, SequenceLoad, SequenceMode,
+    CounterMode, Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm,
 };
 use embassy_nrf::Peripherals;
 use micromath::F32Ext;
@@ -32,7 +32,9 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         end_delay: 0,
     };
 
-    let pwm = unwrap!(PwmSeq::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config));
+    let pwm = unwrap!(SequencePwm::new(
+        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
+    ));
     let _ = pwm.start(SequenceMode::Infinite);
     info!("pwm started!");
 

From b726ef1886c65ab76b01f2c54ad559573e19083d Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:37:54 -0700
Subject: [PATCH 29/47] make SequenceConfig struct is consistent with other
 Config structs, that are always non_exhaustive and have a Default

---
 embassy-nrf/src/pwm.rs                 | 143 ++++++++++++++-----------
 examples/nrf/src/bin/pwm_sequence.rs   |  25 +++--
 examples/nrf/src/bin/pwm_simple_sin.rs |  24 ++---
 3 files changed, 101 insertions(+), 91 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 0d06f845..9f88633c 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -12,43 +12,6 @@ use crate::interrupt::Interrupt;
 use crate::pac;
 use crate::util::slice_in_ram_or;
 
-/// PWM Base clock is system clock (16MHz) divided by prescaler
-#[derive(Debug, Eq, PartialEq, Clone, Copy)]
-pub enum Prescaler {
-    Div1,
-    Div2,
-    Div4,
-    Div8,
-    Div16,
-    Div32,
-    Div64,
-    Div128,
-}
-
-/// How the sequence values are distributed across the channels
-#[derive(Debug, Eq, PartialEq, Clone, Copy)]
-pub enum SequenceLoad {
-    /// Provided sequence will be used across all channels
-    Common,
-    /// Provided sequence contains grouped values for each channel ex:
-    /// [ch0_0_and_ch1_0, ch2_0_and_ch3_0, ... ch0_n_and_ch1_n, ch2_n_and_ch3_n]
-    Grouped,
-    /// Provided sequence contains individual values for each channel ex:
-    /// [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
-    Individual,
-    /// Similar to Individual mode, but only three channels are used. The fourth
-    /// value is loaded into the pulse generator counter as its top value.
-    Waveform,
-}
-
-#[derive(Debug, Eq, PartialEq, Clone, Copy)]
-pub enum CounterMode {
-    /// Up counter (edge-aligned PWM duty cycle)
-    Up,
-    /// Up and down counter (center-aligned PWM duty cycle)
-    UpAndDown,
-}
-
 /// Interface to the PWM peripheral
 pub struct SimplePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
@@ -58,6 +21,18 @@ pub struct SequencePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+#[non_exhaustive]
+pub enum Error {
+    /// Max Sequence size is 32767
+    SequenceTooLong,
+    /// Min Sequence count is 1
+    SequenceTimesAtLeastOne,
+    /// EasyDMA can only read from data memory, read only buffers in flash will fail.
+    DMABufferNotInDataMemory,
+}
+
 impl<'d, T: Instance> SequencePwm<'d, T> {
     /// Creates the interface to a PWM Sequence interface.
     ///
@@ -69,17 +44,18 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
     /// mechanisms) on stack allocated buffers which which have been passed to
     /// [`new()`](SequencePwm::new).
     #[allow(unused_unsafe)]
-    pub fn new(
+    pub fn new<'a>(
         _pwm: impl Unborrow<Target = T> + 'd,
         ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         ch1: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         ch2: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         ch3: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
         config: SequenceConfig,
+        sequence: &'a [u16],
     ) -> Result<Self, Error> {
-        slice_in_ram_or(config.sequence, Error::DMABufferNotInDataMemory)?;
+        slice_in_ram_or(sequence, Error::DMABufferNotInDataMemory)?;
 
-        if config.sequence.len() > 32767 {
+        if sequence.len() > 32767 {
             return Err(Error::SequenceTooLong);
         }
 
@@ -120,10 +96,10 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
         r.seq0
             .ptr
-            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+            .write(|w| unsafe { w.bits(sequence.as_ptr() as u32) });
         r.seq0
             .cnt
-            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+            .write(|w| unsafe { w.bits(sequence.len() as u32) });
         r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq0
             .enddelay
@@ -131,10 +107,10 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
         r.seq1
             .ptr
-            .write(|w| unsafe { w.bits(config.sequence.as_ptr() as u32) });
+            .write(|w| unsafe { w.bits(sequence.as_ptr() as u32) });
         r.seq1
             .cnt
-            .write(|w| unsafe { w.bits(config.sequence.len() as u32) });
+            .write(|w| unsafe { w.bits(sequence.len() as u32) });
         r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
         r.seq1
             .enddelay
@@ -237,24 +213,15 @@ impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
     }
 }
 
-#[derive(Debug, Eq, PartialEq, Clone, Copy)]
-pub enum SequenceMode {
-    /// Run sequence n Times total
-    Times(u16),
-    /// Repeat until `stop` is called.
-    Infinite,
-}
-
 /// Configure an infinite looping sequence for `simple_playback`
-pub struct SequenceConfig<'a> {
+#[non_exhaustive]
+pub struct SequenceConfig {
     /// Selects up mode or up-and-down mode for the counter
     pub counter_mode: CounterMode,
     /// Top value to be compared against buffer values
     pub top: u16,
     /// Configuration for PWM_CLK
     pub prescaler: Prescaler,
-    /// In ram buffer to be played back
-    pub sequence: &'a [u16],
     /// How a sequence is read from RAM and is spread to the compare register
     pub sequence_load: SequenceLoad,
     /// Number of Times PWM periods to delay between each sequence sample
@@ -263,16 +230,62 @@ pub struct SequenceConfig<'a> {
     pub end_delay: u32,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-#[non_exhaustive]
-pub enum Error {
-    /// Max Sequence size is 32767
-    SequenceTooLong,
-    /// Min Sequence size is 1
-    SequenceTimesAtLeastOne,
-    /// EasyDMA can only read from data memory, read only buffers in flash will fail.
-    DMABufferNotInDataMemory,
+impl Default for SequenceConfig {
+    fn default() -> SequenceConfig {
+        SequenceConfig {
+            counter_mode: CounterMode::Up,
+            top: 1000,
+            prescaler: Prescaler::Div16,
+            sequence_load: SequenceLoad::Common,
+            refresh: 0,
+            end_delay: 0,
+        }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum SequenceMode {
+    /// Run sequence n Times total
+    Times(u16),
+    /// Repeat until `stop` is called.
+    Infinite,
+}
+
+/// PWM Base clock is system clock (16MHz) divided by prescaler
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum Prescaler {
+    Div1,
+    Div2,
+    Div4,
+    Div8,
+    Div16,
+    Div32,
+    Div64,
+    Div128,
+}
+
+/// How the sequence values are distributed across the channels
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum SequenceLoad {
+    /// Provided sequence will be used across all channels
+    Common,
+    /// Provided sequence contains grouped values for each channel ex:
+    /// [ch0_0_and_ch1_0, ch2_0_and_ch3_0, ... ch0_n_and_ch1_n, ch2_n_and_ch3_n]
+    Grouped,
+    /// Provided sequence contains individual values for each channel ex:
+    /// [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
+    Individual,
+    /// Similar to Individual mode, but only three channels are used. The fourth
+    /// value is loaded into the pulse generator counter as its top value.
+    Waveform,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum CounterMode {
+    /// Up counter (edge-aligned PWM duty cycle)
+    Up,
+    /// Up and down counter (center-aligned PWM duty cycle)
+    UpAndDown,
 }
 
 impl<'d, T: Instance> SimplePwm<'d, T> {
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 82575d70..3f8b051d 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,9 +7,7 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{
-    CounterMode, Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm,
-};
+use embassy_nrf::pwm::{Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
@@ -18,18 +16,19 @@ async fn main(_spawner: Spawner, p: Peripherals) {
         0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
     ];
 
-    let config = SequenceConfig {
-        counter_mode: CounterMode::Up,
-        top: 15625,
-        prescaler: Prescaler::Div128,
-        sequence: &seq_values,
-        sequence_load: SequenceLoad::Individual,
-        refresh: 0,
-        end_delay: 0,
-    };
+    let mut config = SequenceConfig::default();
+    config.top = 15625;
+    config.prescaler = Prescaler::Div128;
+    config.sequence_load = SequenceLoad::Individual;
 
     let pwm = unwrap!(SequencePwm::new(
-        p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
+        p.PWM0,
+        p.P0_13,
+        p.P0_15,
+        p.P0_16,
+        p.P0_14,
+        config,
+        &seq_values,
     ));
     let _ = pwm.start(SequenceMode::Times(5));
     info!("pwm started!");
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
index afafb5d9..33fa6dcf 100644
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ b/examples/nrf/src/bin/pwm_simple_sin.rs
@@ -9,9 +9,7 @@ use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
 use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{
-    CounterMode, Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm,
-};
+use embassy_nrf::pwm::{CounterMode, SequenceConfig, SequenceMode, SequencePwm};
 use embassy_nrf::Peripherals;
 use micromath::F32Ext;
 
@@ -22,18 +20,18 @@ async fn main(_spawner: Spawner, p: Peripherals) {
     // probably not best use of resources to create the table at runtime, but makes testing fast
     let seq_values: [u16; 220] = core::array::from_fn(|n| ((W1 * n as f32).sin() * 10000.0) as u16);
 
-    let config = SequenceConfig {
-        counter_mode: CounterMode::UpAndDown,
-        top: 12000,
-        prescaler: Prescaler::Div16,
-        sequence: &seq_values,
-        sequence_load: SequenceLoad::Common,
-        refresh: 0,
-        end_delay: 0,
-    };
+    let mut config = SequenceConfig::default();
+    config.counter_mode = CounterMode::UpAndDown;
+    config.top = 12000;
 
     let pwm = unwrap!(SequencePwm::new(
-        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
+        p.PWM0,
+        p.P0_13,
+        NoPin,
+        NoPin,
+        NoPin,
+        config,
+        &seq_values
     ));
     let _ = pwm.start(SequenceMode::Infinite);
     info!("pwm started!");

From 64e1426b54c41a5b622c666cd7763bb07f73a2c4 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:46:42 -0700
Subject: [PATCH 30/47] clean up some todo comments around infinite play

---
 embassy-nrf/src/pwm.rs | 2 --
 1 file changed, 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 9f88633c..b0acd83c 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -146,7 +146,6 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
         r.enable.write(|w| w.enable().enabled());
 
         match times {
-            // todo why doesn't this play forever? set_duty does...
             // just the one time, no loop count
             SequenceMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
@@ -400,7 +399,6 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         // todo justify? should i fence elsehwere we task start? or
         compiler_fence(Ordering::SeqCst);
 
-        // todo why does this play forever when times(1) doesn't?
         // tasks_seqstart() doesn't exist in all svds so write its bit instead
         r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
     }

From 03f2c593d6b919716d44478087f0dec6d4648382 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 3 Nov 2021 18:56:02 -0700
Subject: [PATCH 31/47] fix slice_in_ram for arbitrary size types

---
 embassy-nrf/src/util.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/util.rs b/embassy-nrf/src/util.rs
index d17ec503..2fd0bc5a 100644
--- a/embassy-nrf/src/util.rs
+++ b/embassy-nrf/src/util.rs
@@ -4,13 +4,13 @@ const SRAM_UPPER: usize = 0x3000_0000;
 /// Does this slice reside entirely within RAM?
 pub(crate) fn slice_in_ram<T>(slice: &[T]) -> bool {
     let ptr = slice.as_ptr() as usize;
-    ptr >= SRAM_LOWER && (ptr + slice.len()) < SRAM_UPPER
+    ptr >= SRAM_LOWER && (ptr + slice.len() * core::mem::size_of::<T>()) < SRAM_UPPER
 }
 
 /// Return an error if slice is not in RAM.
 #[cfg(not(feature = "nrf51"))]
 pub(crate) fn slice_in_ram_or<T, E>(slice: &[T], err: E) -> Result<(), E> {
-    if slice.len() == 0 || slice_in_ram(slice) {
+    if slice.is_empty() || slice_in_ram(slice) {
         Ok(())
     } else {
         Err(err)

From 65843c033ed592b879d89ee74eec20b2f78f6cd8 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 11:02:43 -0700
Subject: [PATCH 32/47] pwm store and deconfigure pins

---
 embassy-nrf/src/pwm.rs | 58 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 51 insertions(+), 7 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index b0acd83c..8a6ed27f 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -7,7 +7,7 @@ use embassy::util::Unborrow;
 use embassy_hal_common::unborrow;
 
 use crate::gpio::sealed::Pin as _;
-use crate::gpio::OptionalPin as GpioOptionalPin;
+use crate::gpio::{AnyPin, OptionalPin as GpioOptionalPin, Pin};
 use crate::interrupt::Interrupt;
 use crate::pac;
 use crate::util::slice_in_ram_or;
@@ -15,10 +15,18 @@ use crate::util::slice_in_ram_or;
 /// Interface to the PWM peripheral
 pub struct SimplePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
+    ch0: Option<AnyPin>,
+    ch1: Option<AnyPin>,
+    ch2: Option<AnyPin>,
+    ch3: Option<AnyPin>,
 }
 
 pub struct SequencePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
+    ch0: Option<AnyPin>,
+    ch1: Option<AnyPin>,
+    ch2: Option<AnyPin>,
+    ch3: Option<AnyPin>,
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
@@ -130,6 +138,10 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
         Ok(Self {
             phantom: PhantomData,
+            ch0: ch0.degrade_optional(),
+            ch1: ch1.degrade_optional(),
+            ch2: ch2.degrade_optional(),
+            ch3: ch3.degrade_optional(),
         })
     }
 
@@ -206,9 +218,24 @@ impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
         self.stop();
         self.disable();
 
-        info!("pwm drop: done");
+        if let Some(pin) = &self.ch0 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch1 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch2 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch3 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
 
-        // TODO: disable pins
+        info!("pwm drop: done");
     }
 }
 
@@ -360,6 +387,10 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
 
         Self {
             phantom: PhantomData,
+            ch0: ch0.degrade_optional(),
+            ch1: ch1.degrade_optional(),
+            ch2: ch2.degrade_optional(),
+            ch3: ch3.degrade_optional(),
         }
     }
 
@@ -374,7 +405,6 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
 
-    // todo should this do.. something useful
     /// Enables the PWM generator.
     #[inline(always)]
     pub fn enable(&self) {
@@ -382,7 +412,6 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         r.enable.write(|w| w.enable().enabled());
     }
 
-    // todo should this stop the task? or should you just use set_duty to 0?
     /// Disables the PWM generator.
     #[inline(always)]
     pub fn disable(&self) {
@@ -461,9 +490,24 @@ impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
         self.stop();
         self.disable();
 
-        info!("pwm drop: done");
+        if let Some(pin) = &self.ch0 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch1 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch2 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
+        if let Some(pin) = &self.ch3 {
+            pin.set_low();
+            pin.conf().write(|w| w);
+        }
 
-        // TODO: disable pins
+        info!("pwm drop: done");
     }
 }
 

From 9548748c263a5f34b8b1e26a679b9bb77af01b0a Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 12:29:13 -0700
Subject: [PATCH 33/47] fix

---
 embassy-nrf/src/pwm.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 8a6ed27f..6387cd99 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -7,7 +7,7 @@ use embassy::util::Unborrow;
 use embassy_hal_common::unborrow;
 
 use crate::gpio::sealed::Pin as _;
-use crate::gpio::{AnyPin, OptionalPin as GpioOptionalPin, Pin};
+use crate::gpio::{AnyPin, OptionalPin as GpioOptionalPin};
 use crate::interrupt::Interrupt;
 use crate::pac;
 use crate::util::slice_in_ram_or;

From 4751dbddc6466c30cd1bdd387adb9513ec19b3d2 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 12:32:28 -0700
Subject: [PATCH 34/47] move state into PwmSimple

---
 embassy-nrf/src/pwm.rs | 51 +++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 31 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 6387cd99..077a27cd 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -1,6 +1,5 @@
 #![macro_use]
 
-use core::cell::UnsafeCell;
 use core::marker::PhantomData;
 use core::sync::atomic::{compiler_fence, Ordering};
 use embassy::util::Unborrow;
@@ -15,6 +14,7 @@ use crate::util::slice_in_ram_or;
 /// Interface to the PWM peripheral
 pub struct SimplePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
+    duty: [u16; 4],
     ch0: Option<AnyPin>,
     ch1: Option<AnyPin>,
     ch2: Option<AnyPin>,
@@ -336,7 +336,6 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         unborrow!(ch0, ch1, ch2, ch3);
 
         let r = T::regs();
-        let s = T::state();
 
         if let Some(pin) = ch0.pin_mut() {
             pin.set_low();
@@ -362,6 +361,15 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
         r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
 
+        let pwm = Self {
+            phantom: PhantomData,
+            ch0: ch0.degrade_optional(),
+            ch1: ch1.degrade_optional(),
+            ch2: ch2.degrade_optional(),
+            ch3: ch3.degrade_optional(),
+            duty: [0; 4],
+        };
+
         // Disable all interrupts
         r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
         r.shorts.reset();
@@ -371,7 +379,8 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
 
         r.seq0
             .ptr
-            .write(|w| unsafe { w.bits(&s.duty as *const _ as u32) });
+            .write(|w| unsafe { w.bits(&pwm.duty as *const _ as u32) });
+
         r.seq0.cnt.write(|w| unsafe { w.bits(4) });
         r.seq0.refresh.write(|w| unsafe { w.bits(0) });
         r.seq0.enddelay.write(|w| unsafe { w.bits(0) });
@@ -385,13 +394,7 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         r.countertop.write(|w| unsafe { w.countertop().bits(1000) });
         r.loop_.write(|w| w.cnt().disabled());
 
-        Self {
-            phantom: PhantomData,
-            ch0: ch0.degrade_optional(),
-            ch1: ch1.degrade_optional(),
-            ch2: ch2.degrade_optional(),
-            ch3: ch3.degrade_optional(),
-        }
+        pwm
     }
 
     /// Stop playback
@@ -420,10 +423,14 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
     }
 
     /// Sets duty cycle (15 bit) for a PWM channel.
-    pub fn set_duty(&self, channel: usize, duty: u16) {
+    pub fn set_duty(&mut self, channel: usize, duty: u16) {
         let r = T::regs();
-        let s = T::state();
-        unsafe { (*s.duty.get())[channel] = duty & 0x7FFF };
+
+        self.duty[channel] = duty & 0x7FFF;
+
+        r.seq0
+            .ptr
+            .write(|w| unsafe { w.bits(&self.duty as *const _ as u32) });
 
         // todo justify? should i fence elsehwere we task start? or
         compiler_fence(Ordering::SeqCst);
@@ -514,22 +521,8 @@ impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
 pub(crate) mod sealed {
     use super::*;
 
-    pub struct State {
-        pub duty: UnsafeCell<[u16; 4]>,
-    }
-    unsafe impl Sync for State {}
-
-    impl State {
-        pub const fn new() -> Self {
-            Self {
-                duty: UnsafeCell::new([0; 4]),
-            }
-        }
-    }
-
     pub trait Instance {
         fn regs() -> &'static pac::pwm0::RegisterBlock;
-        fn state() -> &'static State;
     }
 }
 
@@ -543,10 +536,6 @@ macro_rules! impl_pwm {
             fn regs() -> &'static pac::pwm0::RegisterBlock {
                 unsafe { &*pac::$pac_type::ptr() }
             }
-            fn state() -> &'static crate::pwm::sealed::State {
-                static STATE: crate::pwm::sealed::State = crate::pwm::sealed::State::new();
-                &STATE
-            }
         }
         impl crate::pwm::Instance for peripherals::$type {
             type Interrupt = crate::interrupt::$irq;

From 903b8f032fa36fb1bf8cd6f1d1b3c14ce7caa0dd Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 12:34:41 -0700
Subject: [PATCH 35/47] defensive dma

---
 embassy-nrf/src/pwm.rs | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 077a27cd..e4ddda39 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -3,7 +3,7 @@
 use core::marker::PhantomData;
 use core::sync::atomic::{compiler_fence, Ordering};
 use embassy::util::Unborrow;
-use embassy_hal_common::unborrow;
+use embassy_hal_common::{low_power_wait_until, unborrow};
 
 use crate::gpio::sealed::Pin as _;
 use crate::gpio::{AnyPin, OptionalPin as GpioOptionalPin};
@@ -157,12 +157,19 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
         r.enable.write(|w| w.enable().enabled());
 
+        // defensive before seqstart
+        compiler_fence(Ordering::SeqCst);
+
         match times {
             // just the one time, no loop count
             SequenceMode::Times(1) => {
                 r.loop_.write(|w| w.cnt().disabled());
                 // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+
+                // defensive wait until waveform is loaded after seqstart
+                low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                r.events_seqend[0].write(|w| w);
             }
             // loop count is how many times to play BOTH sequences
             // 2 total  (1 x 2)
@@ -177,17 +184,30 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                 if odd {
                     // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
+
+                    // defensive wait until waveform is loaded after seqstart
+                    low_power_wait_until(|| r.events_seqend[1].read().bits() == 1);
+                    r.events_seqend[1].write(|w| w);
                 } else {
                     // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+
+                    // defensive wait until waveform is loaded after seqstart
+                    low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                    r.events_seqend[0].write(|w| w);
                 }
             }
             // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
             SequenceMode::Infinite => {
                 r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
                 r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
+
                 // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
+
+                // defensive wait until waveform is loaded after seqstart
+                low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                r.events_seqend[0].write(|w| w);
             }
         }
 
@@ -201,6 +221,8 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
         r.shorts.reset();
 
+        compiler_fence(Ordering::SeqCst);
+
         // tasks_stop() doesn't exist in all svds so write its bit instead
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
@@ -404,6 +426,8 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
 
         r.shorts.reset();
 
+        compiler_fence(Ordering::SeqCst);
+
         // tasks_stop() doesn't exist in all svds so write its bit instead
         r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
     }
@@ -432,11 +456,15 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
             .ptr
             .write(|w| unsafe { w.bits(&self.duty as *const _ as u32) });
 
-        // todo justify? should i fence elsehwere we task start? or
+        // defensive before seqstart
         compiler_fence(Ordering::SeqCst);
 
         // tasks_seqstart() doesn't exist in all svds so write its bit instead
         r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
+
+        // defensive wait until waveform is loaded after seqstart
+        low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+        r.events_seqend[0].write(|w| w);
     }
 
     /// Sets the PWM clock prescaler.

From 751617c2be10c047ccf6986ace489999b80a01b0 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 12:48:15 -0700
Subject: [PATCH 36/47] fix examples for mut self set_duty

---
 examples/nrf/src/bin/pwm.rs       | 2 +-
 examples/nrf/src/bin/pwm_led.rs   | 2 +-
 examples/nrf/src/bin/pwm_servo.rs | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/examples/nrf/src/bin/pwm.rs b/examples/nrf/src/bin/pwm.rs
index 0cb91cf1..8679eddd 100644
--- a/examples/nrf/src/bin/pwm.rs
+++ b/examples/nrf/src/bin/pwm.rs
@@ -85,7 +85,7 @@ static DUTY: [u16; 1024] = [
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = SimplePwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
+    let mut pwm = SimplePwm::new(p.PWM0, p.P0_13, p.P0_14, p.P0_16, p.P0_15);
     pwm.set_prescaler(Prescaler::Div1);
     pwm.set_max_duty(32767);
     info!("pwm initialized!");
diff --git a/examples/nrf/src/bin/pwm_led.rs b/examples/nrf/src/bin/pwm_led.rs
index ced6a713..d0b71a5c 100644
--- a/examples/nrf/src/bin/pwm_led.rs
+++ b/examples/nrf/src/bin/pwm_led.rs
@@ -13,7 +13,7 @@ use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = SimplePwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
+    let mut pwm = SimplePwm::new(p.PWM0, p.P0_13, NoPin, NoPin, NoPin);
     // set_period doesnt actually set what you give it, because it only has a
     // few options from the hardhware so be explicit instead
     // Div128 is slowest, 125khz still crazy fast for our eyes
diff --git a/examples/nrf/src/bin/pwm_servo.rs b/examples/nrf/src/bin/pwm_servo.rs
index d681a201..700b8857 100644
--- a/examples/nrf/src/bin/pwm_servo.rs
+++ b/examples/nrf/src/bin/pwm_servo.rs
@@ -13,7 +13,7 @@ use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let pwm = SimplePwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
+    let mut pwm = SimplePwm::new(p.PWM0, p.P0_05, NoPin, NoPin, NoPin);
     // sg90 microervo requires 50hz or 20ms period
     // set_period can only set down to 125khz so we cant use it directly
     // Div128 is 125khz or 0.000008s or 0.008ms, 20/0.008 is 2500 is top

From 3b7af2f4edccc57d31c6db5644b3f1384600f0fd Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 13:01:39 -0700
Subject: [PATCH 37/47] fix wait seqend, pwm example is slow now...

---
 embassy-nrf/src/pwm.rs | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index e4ddda39..f0436b5b 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -3,7 +3,7 @@
 use core::marker::PhantomData;
 use core::sync::atomic::{compiler_fence, Ordering};
 use embassy::util::Unborrow;
-use embassy_hal_common::{low_power_wait_until, unborrow};
+use embassy_hal_common::unborrow;
 
 use crate::gpio::sealed::Pin as _;
 use crate::gpio::{AnyPin, OptionalPin as GpioOptionalPin};
@@ -168,7 +168,7 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
 
                 // defensive wait until waveform is loaded after seqstart
-                low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                while r.events_seqend[0].read().bits() == 0 {}
                 r.events_seqend[0].write(|w| w);
             }
             // loop count is how many times to play BOTH sequences
@@ -186,14 +186,14 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
 
                     // defensive wait until waveform is loaded after seqstart
-                    low_power_wait_until(|| r.events_seqend[1].read().bits() == 1);
+                    while r.events_seqend[1].read().bits() == 0 {}
                     r.events_seqend[1].write(|w| w);
                 } else {
                     // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
 
                     // defensive wait until waveform is loaded after seqstart
-                    low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                    while r.events_seqend[0].read().bits() == 0 {}
                     r.events_seqend[0].write(|w| w);
                 }
             }
@@ -206,7 +206,7 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
 
                 // defensive wait until waveform is loaded after seqstart
-                low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+                while r.events_seqend[0].read().bits() == 0 {}
                 r.events_seqend[0].write(|w| w);
             }
         }
@@ -463,7 +463,7 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
         r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
 
         // defensive wait until waveform is loaded after seqstart
-        low_power_wait_until(|| r.events_seqend[0].read().bits() == 1);
+        while r.events_seqend[0].read().bits() == 0 {}
         r.events_seqend[0].write(|w| w);
     }
 

From 5f28153b811caf1e47b51d87eae74d36eeff9a7e Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 17:19:03 -0700
Subject: [PATCH 38/47] disconnect pwm pins on drop

---
 embassy-nrf/src/pwm.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index f0436b5b..252e6385 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -237,24 +237,30 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
 impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
     fn drop(&mut self) {
+        let r = T::regs();
+
         self.stop();
         self.disable();
 
         if let Some(pin) = &self.ch0 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[0].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch1 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[1].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch2 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[2].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch3 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[3].write(|w| unsafe { w.bits(0x80000000) });
         }
 
         info!("pwm drop: done");
@@ -522,24 +528,30 @@ impl<'d, T: Instance> SimplePwm<'d, T> {
 
 impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
     fn drop(&mut self) {
+        let r = T::regs();
+
         self.stop();
         self.disable();
 
         if let Some(pin) = &self.ch0 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[0].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch1 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[1].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch2 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[2].write(|w| unsafe { w.bits(0x80000000) });
         }
         if let Some(pin) = &self.ch3 {
             pin.set_low();
             pin.conf().write(|w| w);
+            r.psel.out[3].write(|w| unsafe { w.bits(0x80000000) });
         }
 
         info!("pwm drop: done");

From 6dcc731065ff7a4e9515f21172b309f50155c353 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 17:25:38 -0700
Subject: [PATCH 39/47] drop the debug

---
 embassy-nrf/src/pwm.rs | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 252e6385..c91cf9a7 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -262,8 +262,6 @@ impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
             pin.conf().write(|w| w);
             r.psel.out[3].write(|w| unsafe { w.bits(0x80000000) });
         }
-
-        info!("pwm drop: done");
     }
 }
 
@@ -553,8 +551,6 @@ impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
             pin.conf().write(|w| w);
             r.psel.out[3].write(|w| unsafe { w.bits(0x80000000) });
         }
-
-        info!("pwm drop: done");
     }
 }
 

From c450f91bd9c1ad37f5556c0b8378271b5d306b9a Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 17:30:59 -0700
Subject: [PATCH 40/47] doc comment cleanup

---
 embassy-nrf/src/pwm.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index c91cf9a7..c8e39113 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -265,7 +265,7 @@ impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
     }
 }
 
-/// Configure an infinite looping sequence for `simple_playback`
+/// Configure an infinite looping sequence for `SequencePwm`
 #[non_exhaustive]
 pub struct SequenceConfig {
     /// Selects up mode or up-and-down mode for the counter
@@ -295,6 +295,7 @@ impl Default for SequenceConfig {
     }
 }
 
+/// How many times to run the sequence
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum SequenceMode {
     /// Run sequence n Times total
@@ -332,6 +333,7 @@ pub enum SequenceLoad {
     Waveform,
 }
 
+/// Selects up mode or up-and-down mode for the counter
 #[derive(Debug, Eq, PartialEq, Clone, Copy)]
 pub enum CounterMode {
     /// Up counter (edge-aligned PWM duty cycle)
@@ -343,7 +345,7 @@ pub enum CounterMode {
 impl<'d, T: Instance> SimplePwm<'d, T> {
     /// Creates the interface to a PWM instance.
     ///
-    /// Defaults the freq to 1Mhz, max_duty 32767, duty 0, and channels low.
+    /// Defaults the freq to 1Mhz, max_duty 1000, duty 0, and pins low.
     /// Must be started by calling `set_duty`
     ///
     /// # Safety

From 2973ff4cf05458cb80718c35c7fe9fa690d0cf8b Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 18:49:24 -0700
Subject: [PATCH 41/47] remove unstable feature and dependency, and make
 pwm_sequence a near mirror of pwm example

---
 examples/nrf/Cargo.toml                |  1 -
 examples/nrf/src/bin/pwm_sequence.rs   | 98 +++++++++++++++++++++++---
 examples/nrf/src/bin/pwm_simple_sin.rs | 47 ------------
 3 files changed, 87 insertions(+), 59 deletions(-)
 delete mode 100644 examples/nrf/src/bin/pwm_simple_sin.rs

diff --git a/examples/nrf/Cargo.toml b/examples/nrf/Cargo.toml
index e0025b73..b89aa513 100644
--- a/examples/nrf/Cargo.toml
+++ b/examples/nrf/Cargo.toml
@@ -31,4 +31,3 @@ panic-probe = { version = "0.2.0", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 rand = { version = "0.8.4", default-features = false }
 embedded-storage = "0.2.0"
-micromath = "2.0.0"
\ No newline at end of file
diff --git a/examples/nrf/src/bin/pwm_sequence.rs b/examples/nrf/src/bin/pwm_sequence.rs
index 3f8b051d..d02b0c9c 100644
--- a/examples/nrf/src/bin/pwm_sequence.rs
+++ b/examples/nrf/src/bin/pwm_sequence.rs
@@ -7,30 +7,106 @@ mod example_common;
 use defmt::*;
 use embassy::executor::Spawner;
 use embassy::time::{Duration, Timer};
-use embassy_nrf::pwm::{Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm};
+use embassy_nrf::gpio::NoPin;
+use embassy_nrf::pwm::{Prescaler, SequenceConfig, SequenceMode, SequencePwm};
 use embassy_nrf::Peripherals;
 
 #[embassy::main]
 async fn main(_spawner: Spawner, p: Peripherals) {
-    let seq_values: [u16; 16] = [
-        0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
+    // for i in range(1024): print(int((math.sin(i/512*math.pi)*0.4+0.5)**2*32767), ', ', end='')
+    let seq_values: [u16; 1024] = [
+        8191, 8272, 8353, 8434, 8516, 8598, 8681, 8764, 8847, 8931, 9015, 9099, 9184, 9269, 9354,
+        9440, 9526, 9613, 9700, 9787, 9874, 9962, 10050, 10139, 10227, 10316, 10406, 10495, 10585,
+        10675, 10766, 10857, 10948, 11039, 11131, 11223, 11315, 11407, 11500, 11592, 11685, 11779,
+        11872, 11966, 12060, 12154, 12248, 12343, 12438, 12533, 12628, 12723, 12818, 12914, 13010,
+        13106, 13202, 13298, 13394, 13491, 13587, 13684, 13781, 13878, 13975, 14072, 14169, 14266,
+        14364, 14461, 14558, 14656, 14754, 14851, 14949, 15046, 15144, 15242, 15339, 15437, 15535,
+        15632, 15730, 15828, 15925, 16023, 16120, 16218, 16315, 16412, 16510, 16607, 16704, 16801,
+        16898, 16995, 17091, 17188, 17284, 17380, 17477, 17572, 17668, 17764, 17859, 17955, 18050,
+        18145, 18239, 18334, 18428, 18522, 18616, 18710, 18803, 18896, 18989, 19082, 19174, 19266,
+        19358, 19449, 19540, 19631, 19722, 19812, 19902, 19991, 20081, 20169, 20258, 20346, 20434,
+        20521, 20608, 20695, 20781, 20867, 20952, 21037, 21122, 21206, 21290, 21373, 21456, 21538,
+        21620, 21701, 21782, 21863, 21943, 22022, 22101, 22179, 22257, 22335, 22412, 22488, 22564,
+        22639, 22714, 22788, 22861, 22934, 23007, 23079, 23150, 23220, 23290, 23360, 23429, 23497,
+        23564, 23631, 23698, 23763, 23828, 23892, 23956, 24019, 24081, 24143, 24204, 24264, 24324,
+        24383, 24441, 24499, 24555, 24611, 24667, 24721, 24775, 24828, 24881, 24933, 24983, 25034,
+        25083, 25132, 25180, 25227, 25273, 25319, 25363, 25407, 25451, 25493, 25535, 25575, 25615,
+        25655, 25693, 25731, 25767, 25803, 25838, 25873, 25906, 25939, 25971, 26002, 26032, 26061,
+        26089, 26117, 26144, 26170, 26195, 26219, 26242, 26264, 26286, 26307, 26327, 26346, 26364,
+        26381, 26397, 26413, 26427, 26441, 26454, 26466, 26477, 26487, 26496, 26505, 26512, 26519,
+        26525, 26530, 26534, 26537, 26539, 26540, 26541, 26540, 26539, 26537, 26534, 26530, 26525,
+        26519, 26512, 26505, 26496, 26487, 26477, 26466, 26454, 26441, 26427, 26413, 26397, 26381,
+        26364, 26346, 26327, 26307, 26286, 26264, 26242, 26219, 26195, 26170, 26144, 26117, 26089,
+        26061, 26032, 26002, 25971, 25939, 25906, 25873, 25838, 25803, 25767, 25731, 25693, 25655,
+        25615, 25575, 25535, 25493, 25451, 25407, 25363, 25319, 25273, 25227, 25180, 25132, 25083,
+        25034, 24983, 24933, 24881, 24828, 24775, 24721, 24667, 24611, 24555, 24499, 24441, 24383,
+        24324, 24264, 24204, 24143, 24081, 24019, 23956, 23892, 23828, 23763, 23698, 23631, 23564,
+        23497, 23429, 23360, 23290, 23220, 23150, 23079, 23007, 22934, 22861, 22788, 22714, 22639,
+        22564, 22488, 22412, 22335, 22257, 22179, 22101, 22022, 21943, 21863, 21782, 21701, 21620,
+        21538, 21456, 21373, 21290, 21206, 21122, 21037, 20952, 20867, 20781, 20695, 20608, 20521,
+        20434, 20346, 20258, 20169, 20081, 19991, 19902, 19812, 19722, 19631, 19540, 19449, 19358,
+        19266, 19174, 19082, 18989, 18896, 18803, 18710, 18616, 18522, 18428, 18334, 18239, 18145,
+        18050, 17955, 17859, 17764, 17668, 17572, 17477, 17380, 17284, 17188, 17091, 16995, 16898,
+        16801, 16704, 16607, 16510, 16412, 16315, 16218, 16120, 16023, 15925, 15828, 15730, 15632,
+        15535, 15437, 15339, 15242, 15144, 15046, 14949, 14851, 14754, 14656, 14558, 14461, 14364,
+        14266, 14169, 14072, 13975, 13878, 13781, 13684, 13587, 13491, 13394, 13298, 13202, 13106,
+        13010, 12914, 12818, 12723, 12628, 12533, 12438, 12343, 12248, 12154, 12060, 11966, 11872,
+        11779, 11685, 11592, 11500, 11407, 11315, 11223, 11131, 11039, 10948, 10857, 10766, 10675,
+        10585, 10495, 10406, 10316, 10227, 10139, 10050, 9962, 9874, 9787, 9700, 9613, 9526, 9440,
+        9354, 9269, 9184, 9099, 9015, 8931, 8847, 8764, 8681, 8598, 8516, 8434, 8353, 8272, 8191,
+        8111, 8031, 7952, 7873, 7794, 7716, 7638, 7561, 7484, 7407, 7331, 7255, 7180, 7105, 7031,
+        6957, 6883, 6810, 6738, 6665, 6594, 6522, 6451, 6381, 6311, 6241, 6172, 6104, 6036, 5968,
+        5901, 5834, 5767, 5702, 5636, 5571, 5507, 5443, 5379, 5316, 5253, 5191, 5130, 5068, 5008,
+        4947, 4888, 4828, 4769, 4711, 4653, 4596, 4539, 4482, 4426, 4371, 4316, 4261, 4207, 4153,
+        4100, 4047, 3995, 3943, 3892, 3841, 3791, 3741, 3691, 3642, 3594, 3546, 3498, 3451, 3404,
+        3358, 3312, 3267, 3222, 3178, 3134, 3090, 3047, 3005, 2962, 2921, 2879, 2839, 2798, 2758,
+        2719, 2680, 2641, 2603, 2565, 2528, 2491, 2454, 2418, 2382, 2347, 2312, 2278, 2244, 2210,
+        2177, 2144, 2112, 2080, 2048, 2017, 1986, 1956, 1926, 1896, 1867, 1838, 1810, 1781, 1754,
+        1726, 1699, 1673, 1646, 1620, 1595, 1570, 1545, 1520, 1496, 1472, 1449, 1426, 1403, 1380,
+        1358, 1336, 1315, 1294, 1273, 1252, 1232, 1212, 1192, 1173, 1154, 1135, 1117, 1099, 1081,
+        1063, 1046, 1029, 1012, 996, 980, 964, 948, 933, 918, 903, 888, 874, 860, 846, 833, 819,
+        806, 793, 781, 768, 756, 744, 733, 721, 710, 699, 688, 677, 667, 657, 647, 637, 627, 618,
+        609, 599, 591, 582, 574, 565, 557, 549, 541, 534, 526, 519, 512, 505, 498, 492, 485, 479,
+        473, 467, 461, 455, 450, 444, 439, 434, 429, 424, 419, 415, 410, 406, 402, 398, 394, 390,
+        386, 383, 379, 376, 373, 370, 367, 364, 361, 359, 356, 354, 351, 349, 347, 345, 343, 342,
+        340, 338, 337, 336, 334, 333, 332, 331, 330, 330, 329, 328, 328, 328, 327, 327, 327, 327,
+        327, 328, 328, 328, 329, 330, 330, 331, 332, 333, 334, 336, 337, 338, 340, 342, 343, 345,
+        347, 349, 351, 354, 356, 359, 361, 364, 367, 370, 373, 376, 379, 383, 386, 390, 394, 398,
+        402, 406, 410, 415, 419, 424, 429, 434, 439, 444, 450, 455, 461, 467, 473, 479, 485, 492,
+        498, 505, 512, 519, 526, 534, 541, 549, 557, 565, 574, 582, 591, 599, 609, 618, 627, 637,
+        647, 657, 667, 677, 688, 699, 710, 721, 733, 744, 756, 768, 781, 793, 806, 819, 833, 846,
+        860, 874, 888, 903, 918, 933, 948, 964, 980, 996, 1012, 1029, 1046, 1063, 1081, 1099, 1117,
+        1135, 1154, 1173, 1192, 1212, 1232, 1252, 1273, 1294, 1315, 1336, 1358, 1380, 1403, 1426,
+        1449, 1472, 1496, 1520, 1545, 1570, 1595, 1620, 1646, 1673, 1699, 1726, 1754, 1781, 1810,
+        1838, 1867, 1896, 1926, 1956, 1986, 2017, 2048, 2080, 2112, 2144, 2177, 2210, 2244, 2278,
+        2312, 2347, 2382, 2418, 2454, 2491, 2528, 2565, 2603, 2641, 2680, 2719, 2758, 2798, 2839,
+        2879, 2921, 2962, 3005, 3047, 3090, 3134, 3178, 3222, 3267, 3312, 3358, 3404, 3451, 3498,
+        3546, 3594, 3642, 3691, 3741, 3791, 3841, 3892, 3943, 3995, 4047, 4100, 4153, 4207, 4261,
+        4316, 4371, 4426, 4482, 4539, 4596, 4653, 4711, 4769, 4828, 4888, 4947, 5008, 5068, 5130,
+        5191, 5253, 5316, 5379, 5443, 5507, 5571, 5636, 5702, 5767, 5834, 5901, 5968, 6036, 6104,
+        6172, 6241, 6311, 6381, 6451, 6522, 6594, 6665, 6738, 6810, 6883, 6957, 7031, 7105, 7180,
+        7255, 7331, 7407, 7484, 7561, 7638, 7716, 7794, 7873, 7952, 8031, 8111,
     ];
 
     let mut config = SequenceConfig::default();
-    config.top = 15625;
-    config.prescaler = Prescaler::Div128;
-    config.sequence_load = SequenceLoad::Individual;
+    config.prescaler = Prescaler::Div1;
+    // 1 period is 32767 * 1/16mhz = 0.002047938 = 2.047938ms
+    config.top = 32767;
+    // pwm example is delaying >~3ms before updating duty cycle, our refreshes
+    // happen exactly at 2.047938ms so we need a delay after each value of >~1ms
+    // which for us is ~1-2 periods
+    config.refresh = 3;
 
     let pwm = unwrap!(SequencePwm::new(
         p.PWM0,
         p.P0_13,
-        p.P0_15,
-        p.P0_16,
-        p.P0_14,
+        NoPin,
+        NoPin,
+        NoPin,
         config,
-        &seq_values,
+        &seq_values
     ));
-    let _ = pwm.start(SequenceMode::Times(5));
+    let _ = pwm.start(SequenceMode::Infinite);
     info!("pwm started!");
 
     loop {
diff --git a/examples/nrf/src/bin/pwm_simple_sin.rs b/examples/nrf/src/bin/pwm_simple_sin.rs
deleted file mode 100644
index 33fa6dcf..00000000
--- a/examples/nrf/src/bin/pwm_simple_sin.rs
+++ /dev/null
@@ -1,47 +0,0 @@
-#![no_std]
-#![no_main]
-#![feature(type_alias_impl_trait)]
-#![feature(array_from_fn)]
-
-#[path = "../example_common.rs"]
-mod example_common;
-use defmt::*;
-use embassy::executor::Spawner;
-use embassy::time::{Duration, Timer};
-use embassy_nrf::gpio::NoPin;
-use embassy_nrf::pwm::{CounterMode, SequenceConfig, SequenceMode, SequencePwm};
-use embassy_nrf::Peripherals;
-use micromath::F32Ext;
-
-const W1: f32 = core::f32::consts::PI / 128.0;
-
-#[embassy::main]
-async fn main(_spawner: Spawner, p: Peripherals) {
-    // probably not best use of resources to create the table at runtime, but makes testing fast
-    let seq_values: [u16; 220] = core::array::from_fn(|n| ((W1 * n as f32).sin() * 10000.0) as u16);
-
-    let mut config = SequenceConfig::default();
-    config.counter_mode = CounterMode::UpAndDown;
-    config.top = 12000;
-
-    let pwm = unwrap!(SequencePwm::new(
-        p.PWM0,
-        p.P0_13,
-        NoPin,
-        NoPin,
-        NoPin,
-        config,
-        &seq_values
-    ));
-    let _ = pwm.start(SequenceMode::Infinite);
-    info!("pwm started!");
-
-    Timer::after(Duration::from_millis(20000)).await;
-
-    pwm.stop();
-    info!("pwm stopped!");
-
-    loop {
-        Timer::after(Duration::from_millis(1000)).await;
-    }
-}

From c6736abf5e0f59c0bd96cf6f57c1f23c50fc54cd Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 18:52:03 -0700
Subject: [PATCH 42/47] dont wait seqend for sequencepwm

---
 embassy-nrf/src/pwm.rs | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index c8e39113..a53956c6 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -166,10 +166,6 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                 r.loop_.write(|w| w.cnt().disabled());
                 // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-
-                // defensive wait until waveform is loaded after seqstart
-                while r.events_seqend[0].read().bits() == 0 {}
-                r.events_seqend[0].write(|w| w);
             }
             // loop count is how many times to play BOTH sequences
             // 2 total  (1 x 2)
@@ -184,17 +180,9 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
                 if odd {
                     // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
-
-                    // defensive wait until waveform is loaded after seqstart
-                    while r.events_seqend[1].read().bits() == 0 {}
-                    r.events_seqend[1].write(|w| w);
                 } else {
                     // tasks_seqstart() doesn't exist in all svds so write its bit instead
                     r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-
-                    // defensive wait until waveform is loaded after seqstart
-                    while r.events_seqend[0].read().bits() == 0 {}
-                    r.events_seqend[0].write(|w| w);
                 }
             }
             // to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
@@ -204,10 +192,6 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
 
                 // tasks_seqstart() doesn't exist in all svds so write its bit instead
                 r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
-
-                // defensive wait until waveform is loaded after seqstart
-                while r.events_seqend[0].read().bits() == 0 {}
-                r.events_seqend[0].write(|w| w);
             }
         }
 

From 4c2d0ac211af20aac3e2e0fbef1b540f92247ccb Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 18:52:29 -0700
Subject: [PATCH 43/47] doccomments

---
 embassy-nrf/src/pwm.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index a53956c6..5f31b772 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -260,9 +260,9 @@ pub struct SequenceConfig {
     pub prescaler: Prescaler,
     /// How a sequence is read from RAM and is spread to the compare register
     pub sequence_load: SequenceLoad,
-    /// Number of Times PWM periods to delay between each sequence sample
+    /// Number of PWM periods to delay between each sequence sample
     pub refresh: u32,
-    /// Number of Times PWM periods after the sequence ends before starting the next sequence
+    /// Number of PWM periods after the sequence ends before starting the next sequence
     pub end_delay: u32,
 }
 
@@ -329,7 +329,7 @@ pub enum CounterMode {
 impl<'d, T: Instance> SimplePwm<'d, T> {
     /// Creates the interface to a PWM instance.
     ///
-    /// Defaults the freq to 1Mhz, max_duty 1000, duty 0, and pins low.
+    /// Defaults the freq to 1Mhz, max_duty 1000, duty 0, up mode, and pins low.
     /// Must be started by calling `set_duty`
     ///
     /// # Safety

From 613e88f1d2dad3c8f5ea2471bb5b714e180a5ede Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 18:53:21 -0700
Subject: [PATCH 44/47] fix bug with config.counter_mode

---
 embassy-nrf/src/pwm.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 5f31b772..8c4a5dae 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -129,8 +129,10 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
             w.mode().refresh_count()
         });
 
-        r.mode
-            .write(|w| unsafe { w.bits(config.counter_mode as u32) });
+        r.mode.write(|w| match config.counter_mode {
+            CounterMode::UpAndDown => w.updown().up_and_down(),
+            CounterMode::Up => w.updown().up(),
+        });
         r.prescaler
             .write(|w| w.prescaler().bits(config.prescaler as u8));
         r.countertop

From 407e5d06e09c18a9956fcc4de42deaaaedd35912 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 19:43:47 -0700
Subject: [PATCH 45/47] more comments

---
 embassy-nrf/src/pwm.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 8c4a5dae..5063c945 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -11,7 +11,8 @@ use crate::interrupt::Interrupt;
 use crate::pac;
 use crate::util::slice_in_ram_or;
 
-/// Interface to the PWM peripheral
+/// SimplePwm is the traditional pwm interface you're probably used to, allowing
+/// to simply set a duty cycle across up to four channels.
 pub struct SimplePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
     duty: [u16; 4],
@@ -21,6 +22,8 @@ pub struct SimplePwm<'d, T: Instance> {
     ch3: Option<AnyPin>,
 }
 
+/// SequencePwm allows you to offloader the updating of a sequence of duty
+/// cycles to up to four channels, as well as repeat that sequence n times.
 pub struct SequencePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
     ch0: Option<AnyPin>,
@@ -42,7 +45,7 @@ pub enum Error {
 }
 
 impl<'d, T: Instance> SequencePwm<'d, T> {
-    /// Creates the interface to a PWM Sequence interface.
+    /// Creates the interface to a `SequencePwm`.
     ///
     /// Must be started by calling `start`
     ///
@@ -329,7 +332,7 @@ pub enum CounterMode {
 }
 
 impl<'d, T: Instance> SimplePwm<'d, T> {
-    /// Creates the interface to a PWM instance.
+    /// Creates the interface to a `SimplePwm`
     ///
     /// Defaults the freq to 1Mhz, max_duty 1000, duty 0, up mode, and pins low.
     /// Must be started by calling `set_duty`

From 66a43c2e580880964bb7c518ee898fc76ff00ce8 Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 19:44:57 -0700
Subject: [PATCH 46/47] more comments

---
 embassy-nrf/src/pwm.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index 5063c945..ea629c54 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -22,8 +22,8 @@ pub struct SimplePwm<'d, T: Instance> {
     ch3: Option<AnyPin>,
 }
 
-/// SequencePwm allows you to offloader the updating of a sequence of duty
-/// cycles to up to four channels, as well as repeat that sequence n times.
+/// SequencePwm allows you to offload the updating of a sequence of duty cycles
+/// to up to four channels, as well as repeat that sequence n times.
 pub struct SequencePwm<'d, T: Instance> {
     phantom: PhantomData<&'d mut T>,
     ch0: Option<AnyPin>,

From 156caa9330f4ce8bf9af6b90655e8dbbac6ad74a Mon Sep 17 00:00:00 2001
From: Jacob Rosenthal <jacobrosenthal@gmail.com>
Date: Wed, 10 Nov 2021 19:56:36 -0700
Subject: [PATCH 47/47] more comments

---
 embassy-nrf/src/pwm.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/embassy-nrf/src/pwm.rs b/embassy-nrf/src/pwm.rs
index ea629c54..08e9add0 100644
--- a/embassy-nrf/src/pwm.rs
+++ b/embassy-nrf/src/pwm.rs
@@ -203,7 +203,7 @@ impl<'d, T: Instance> SequencePwm<'d, T> {
         Ok(())
     }
 
-    /// Stop playback
+    /// Stop playback.
     #[inline(always)]
     pub fn stop(&self) {
         let r = T::regs();