PIO support for RPi Pico

embassy-rp/Cargo.toml

@@ -26,6 +26,7 @@ time-driver = []
 rom-func-cache = []
 intrinsics = []
 rom-v2-intrinsics = []
+pio = ["dep:pio", "dep:pio-proc"]
 
 # Enable nightly-only features
 nightly = ["embassy-executor/nightly", "embedded-hal-1", "embedded-hal-async", "embassy-embedded-hal/nightly", "dep:embassy-usb-driver", "dep:embedded-io"]
@@ -64,3 +65,10 @@ embedded-hal-02 = { package = "embedded-hal", version = "0.2.6", features = ["un
 embedded-hal-1 = { package = "embedded-hal", version = "=1.0.0-alpha.9", optional = true}
 embedded-hal-async = { version = "=0.2.0-alpha.0", optional = true}
 embedded-hal-nb = { version = "=1.0.0-alpha.1", optional = true}
+
+paste = "1.0"
+pio-proc = {version= "0.2", optional = true}
+pio = {version= "0.2", optional = true}
+
+[patch.crates-io]
+pio = {git = "https://github.com/rp-rs/pio-rs.git"}

embassy-rp/src/gpio.rs

@@ -48,6 +48,21 @@ pub enum Pull {
     Down,
 }
 
+/// Drive strength of an output
+#[derive(Debug, Eq, PartialEq)]
+pub enum Drive {
+    _2mA,
+    _4mA,
+    _8mA,
+    _12mA,
+}
+/// Slew rate of an output
+#[derive(Debug, Eq, PartialEq)]
+pub enum SlewRate {
+    Fast,
+    Slow,
+}
+
 /// A GPIO bank with up to 32 pins.
 #[derive(Debug, Eq, PartialEq)]
 pub enum Bank {
@@ -459,7 +474,7 @@ impl<'d, T: Pin> Flex<'d, T> {
     #[inline]
     pub fn set_pull(&mut self, pull: Pull) {
         unsafe {
-            self.pin.pad_ctrl().write(|w| {
+            self.pin.pad_ctrl().modify(|w| {
                 w.set_ie(true);
                 match pull {
                     Pull::Up => w.set_pue(true),
@@ -470,6 +485,31 @@ impl<'d, T: Pin> Flex<'d, T> {
         }
     }
 
+    /// Set the pin's drive strength.
+    #[inline]
+    pub fn set_drive_strength(&mut self, strength: Drive) {
+        unsafe {
+            self.pin.pad_ctrl().modify(|w| {
+                w.set_drive(match strength {
+                    Drive::_2mA => pac::pads::vals::Drive::_2MA,
+                    Drive::_4mA => pac::pads::vals::Drive::_4MA,
+                    Drive::_8mA => pac::pads::vals::Drive::_8MA,
+                    Drive::_12mA => pac::pads::vals::Drive::_12MA,
+                });
+            });
+        }
+    }
+
+    // Set the pin's slew rate.
+    #[inline]
+    pub fn set_slew_rate(&mut self, slew_rate: SlewRate) {
+        unsafe {
+            self.pin.pad_ctrl().modify(|w| {
+                w.set_slewfast(slew_rate == SlewRate::Fast);
+            });
+        }
+    }
+
     /// Put the pin into input mode.
     ///
     /// The pull setting is left unchanged.

embassy-rp/src/lib.rs

@@ -12,6 +12,12 @@ pub mod dma;
 pub mod gpio;
 pub mod i2c;
 pub mod interrupt;
+
+#[cfg(feature = "pio")]
+pub mod pio;
+#[cfg(feature = "pio")]
+pub mod pio_instr_util;
+
 pub mod rom_data;
 pub mod rtc;
 pub mod spi;
@@ -102,6 +108,9 @@ embassy_hal_common::peripherals! {
     FLASH,
 
     ADC,
+
+    PIO0,
+    PIO1,
 }
 
 #[link_section = ".boot2"]

embassy-rp/src/pio_instr_util.rs

@@ -0,0 +1,90 @@
+use pio::{InSource, InstructionOperands, JmpCondition, OutDestination, SetDestination};
+
+use crate::pio::PioStateMachine;
+
+pub fn set_x<SM: PioStateMachine>(sm: &mut SM, value: u32) {
+    const OUT: u16 = InstructionOperands::OUT {
+        destination: OutDestination::X,
+        bit_count: 32,
+    }
+    .encode();
+    sm.push_tx(value);
+    sm.exec_instr(OUT);
+}
+
+pub fn get_x<SM: PioStateMachine>(sm: &mut SM) -> u32 {
+    const IN: u16 = InstructionOperands::IN {
+        source: InSource::X,
+        bit_count: 32,
+    }
+    .encode();
+    sm.exec_instr(IN);
+    sm.pull_rx()
+}
+
+pub fn set_y<SM: PioStateMachine>(sm: &mut SM, value: u32) {
+    const OUT: u16 = InstructionOperands::OUT {
+        destination: OutDestination::Y,
+        bit_count: 32,
+    }
+    .encode();
+    sm.push_tx(value);
+    sm.exec_instr(OUT);
+}
+
+pub fn get_y<SM: PioStateMachine>(sm: &mut SM) -> u32 {
+    const IN: u16 = InstructionOperands::IN {
+        source: InSource::Y,
+        bit_count: 32,
+    }
+    .encode();
+    sm.exec_instr(IN);
+
+    sm.pull_rx()
+}
+
+pub fn set_pindir<SM: PioStateMachine>(sm: &mut SM, data: u8) {
+    let set: u16 = InstructionOperands::SET {
+        destination: SetDestination::PINDIRS,
+        data,
+    }
+    .encode();
+    sm.exec_instr(set);
+}
+
+pub fn set_pin<SM: PioStateMachine>(sm: &mut SM, data: u8) {
+    let set: u16 = InstructionOperands::SET {
+        destination: SetDestination::PINS,
+        data,
+    }
+    .encode();
+    sm.exec_instr(set);
+}
+
+pub fn set_out_pin<SM: PioStateMachine>(sm: &mut SM, data: u32) {
+    const OUT: u16 = InstructionOperands::OUT {
+        destination: OutDestination::PINS,
+        bit_count: 32,
+    }
+    .encode();
+    sm.push_tx(data);
+    sm.exec_instr(OUT);
+}
+pub fn set_out_pindir<SM: PioStateMachine>(sm: &mut SM, data: u32) {
+    const OUT: u16 = InstructionOperands::OUT {
+        destination: OutDestination::PINDIRS,
+        bit_count: 32,
+    }
+    .encode();
+    sm.push_tx(data);
+    sm.exec_instr(OUT);
+}
+
+pub fn exec_jmp<SM: PioStateMachine>(sm: &mut SM, to_addr: u8) {
+    let jmp: u16 = InstructionOperands::JMP {
+        address: to_addr,
+        condition: JmpCondition::Always,
+    }
+    .encode();
+    sm.exec_instr(jmp);
+}

examples/rp/Cargo.toml

@@ -9,7 +9,7 @@ license = "MIT OR Apache-2.0"
 embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime"] }
-embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["defmt", "unstable-traits", "nightly", "unstable-pac", "time-driver"] }
+embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["defmt", "unstable-traits", "nightly", "unstable-pac", "time-driver", "pio"] }
 embassy-usb = { version = "0.1.0", path = "../../embassy-usb", features = ["defmt"] }
 embassy-net = { version = "0.1.0", path = "../../embassy-net", features = ["defmt", "nightly", "tcp", "dhcpv4", "medium-ethernet", "pool-16"] }
 embassy-futures = { version = "0.1.0", path = "../../embassy-futures" }
@@ -34,6 +34,11 @@ embedded-io = { version = "0.4.0", features = ["async", "defmt"] }
 embedded-storage = { version = "0.3" }
 static_cell = "1.0.0"
 log = "0.4"
+pio-proc = "0.2"
+pio = "0.2"
 
 [profile.release]
 debug = true
+
+[patch.crates-io]
+pio = {git = "https://github.com/rp-rs/pio-rs.git"}

examples/rp/src/bin/pio_async.rs

@@ -0,0 +1,105 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_rp::gpio::{AnyPin, Pin};
+use embassy_rp::pio::{Pio0, PioPeripherial, PioStateMachine, PioStateMachineInstance, ShiftDirection, Sm0, Sm1, Sm2};
+use embassy_rp::pio_instr_util;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn pio_task_sm0(mut sm: PioStateMachineInstance<Pio0, Sm0>, pin: AnyPin) {
+    // Setup sm0
+
+    // Send data serially to pin
+    let prg = pio_proc::pio_asm!(
+        ".origin 16",
+        "set pindirs, 1",
+        ".wrap_target",
+        "out pins,1 [19]",
+        ".wrap",
+    );
+
+    let origin = prg.program.origin.unwrap_or(0);
+    let out_pin = sm.make_pio_pin(pin);
+    let pio_pins = [&out_pin];
+    sm.set_out_pins(&pio_pins);
+    sm.write_instr(origin as usize, &prg.program.code);
+    pio_instr_util::exec_jmp(&mut sm, origin);
+    sm.set_clkdiv((125e6 / 20.0 / 2e2 * 256.0) as u32);
+    sm.set_set_range(0, 1);
+    sm.set_wrap(prg.program.wrap.source + origin, prg.program.wrap.target + origin);
+    sm.set_autopull(true);
+    sm.set_out_shift_dir(ShiftDirection::Left);
+
+    sm.set_enable(true);
+
+    let mut v = 0x0f0caffa;
+    loop {
+        sm.wait_push(v).await;
+        v ^= 0xffff;
+        info!("Pushed {:032b} to FIFO", v);
+    }
+}
+
+#[embassy_executor::task]
+async fn pio_task_sm1(mut sm: PioStateMachineInstance<Pio0, Sm1>) {
+    // Setupm sm1
+
+    // Read 0b10101 repeatedly until ISR is full
+    let prg = pio_proc::pio_asm!(".origin 8", "set x, 0x15", ".wrap_target", "in x, 5 [31]", ".wrap",);
+
+    let origin = prg.program.origin.unwrap_or(0);
+    sm.write_instr(origin as usize, &prg.program.code);
+    pio_instr_util::exec_jmp(&mut sm, origin);
+    sm.set_clkdiv((125e6 / 2e3 * 256.0) as u32);
+    sm.set_set_range(0, 0);
+    sm.set_wrap(prg.program.wrap.source + origin, prg.program.wrap.target + origin);
+    sm.set_autopush(true);
+    sm.set_in_shift_dir(ShiftDirection::Right);
+    sm.set_enable(true);
+    loop {
+        let rx = sm.wait_pull().await;
+        info!("Pulled {:032b} from FIFO", rx);
+    }
+}
+
+#[embassy_executor::task]
+async fn pio_task_sm2(mut sm: PioStateMachineInstance<Pio0, Sm2>) {
+    // Setup sm2
+
+    // Repeatedly trigger IRQ 3
+    let prg = pio_proc::pio_asm!(
+        ".origin 0",
+        ".wrap_target",
+        "set x,10",
+        "delay:",
+        "jmp x-- delay [15]",
+        "irq 3 [15]",
+        ".wrap",
+    );
+    let origin = prg.program.origin.unwrap_or(0);
+
+    sm.write_instr(origin as usize, &prg.program.code);
+    sm.set_wrap(prg.program.wrap.source + origin, prg.program.wrap.target + origin);
+    pio_instr_util::exec_jmp(&mut sm, origin);
+    sm.set_clkdiv((125e6 / 2e3 * 256.0) as u32);
+    sm.set_enable(true);
+    loop {
+        sm.wait_irq(3).await;
+        info!("IRQ trigged");
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let pio = p.PIO0;
+
+    let (_, sm0, sm1, sm2, ..) = pio.split();
+
+    spawner.spawn(pio_task_sm0(sm0, p.PIN_0.degrade())).unwrap();
+    spawner.spawn(pio_task_sm1(sm1)).unwrap();
+    spawner.spawn(pio_task_sm2(sm2)).unwrap();
+}

examples/rp/src/bin/pio_dma.rs

@@ -0,0 +1,67 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_futures::join::join;
+use embassy_rp::pio::{PioPeripherial, PioStateMachine, ShiftDirection};
+use embassy_rp::{pio_instr_util, Peripheral};
+use {defmt_rtt as _, panic_probe as _};
+
+fn swap_nibbles(v: u32) -> u32 {
+    let v = (v & 0x0f0f_0f0f) << 4 | (v & 0xf0f0_f0f0) >> 4;
+    let v = (v & 0x00ff_00ff) << 8 | (v & 0xff00_ff00) >> 8;
+    (v & 0x0000_ffff) << 16 | (v & 0xffff_0000) >> 16
+}
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let pio = p.PIO0;
+    let (_, mut sm, ..) = pio.split();
+
+    let prg = pio_proc::pio_asm!(
+        ".origin 0",
+        "set pindirs,1",
+        ".wrap_target",
+        "set y,7",
+        "loop:",
+        "out x,4",
+        "in x,4",
+        "jmp y--, loop",
+        ".wrap",
+    );
+
+    let origin = prg.program.origin.unwrap_or(0);
+    sm.write_instr(origin as usize, &prg.program.code);
+    pio_instr_util::exec_jmp(&mut sm, origin);
+    sm.set_clkdiv((125e6 / 10e3 * 256.0) as u32);
+    sm.set_wrap(prg.program.wrap.source + origin, prg.program.wrap.target + origin);
+    sm.set_autopull(true);
+    sm.set_autopush(true);
+    sm.set_pull_threshold(32);
+    sm.set_push_threshold(32);
+    sm.set_out_shift_dir(ShiftDirection::Right);
+    sm.set_in_shift_dir(ShiftDirection::Left);
+
+    sm.set_enable(true);
+
+    let mut dma_out_ref = p.DMA_CH0.into_ref();
+    let mut dma_in_ref = p.DMA_CH1.into_ref();
+    let mut dout = [0x12345678u32; 29];
+    for i in 1..dout.len() {
+        dout[i] = (dout[i - 1] & 0x0fff_ffff) * 13 + 7;
+    }
+    let mut din = [0u32; 29];
+    loop {
+        join(
+            sm.dma_push(dma_out_ref.reborrow(), &dout),
+            sm.dma_pull(dma_in_ref.reborrow(), &mut din),
+        )
+        .await;
+        for i in 0..din.len() {
+            assert_eq!(din[i], swap_nibbles(dout[i]));
+        }
+        info!("Swapped {} words", dout.len());
+    }
+}