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] 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;
+    }
+}