nrf: sequencepwm add events

examples/nrf/src/bin/pwm_sequence_ppi.rs

@@ -0,0 +1,73 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+#![feature(array_from_fn)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use core::future::pending;
+use defmt::*;
+use embassy::executor::Spawner;
+use embassy_nrf::gpio::{Input, NoPin, Pull};
+use embassy_nrf::gpiote::{InputChannel, InputChannelPolarity};
+use embassy_nrf::ppi::Ppi;
+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; 5] = [1000, 250, 100, 50, 0];
+
+    let mut config = SequenceConfig::default();
+    config.prescaler = Prescaler::Div128;
+    // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8ms
+    // but say we want to hold the value for 250ms 250ms/8 = 31.25 periods
+    // so round to 31 - 1 (we get the one period for free remember)
+    // thus our sequence takes 5 * 250ms or 1.25 seconds
+    config.refresh = 30;
+
+    let pwm = unwrap!(SequencePwm::new(
+        p.PWM0,
+        p.P0_13,
+        NoPin,
+        NoPin,
+        NoPin,
+        config,
+        &seq_values
+    ));
+
+    let _ = pwm.start(SequenceMode::Times(1));
+    // pwm.stop() deconfigures pins, and then the task_start_seq0 task cant work
+    // so its going to have to start running in order load the configuration
+
+    let button1 = InputChannel::new(
+        p.GPIOTE_CH0,
+        Input::new(p.P0_11, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+
+    let button2 = InputChannel::new(
+        p.GPIOTE_CH1,
+        Input::new(p.P0_12, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+
+    // messing with the pwm tasks is ill advised
+    // Times::Ininite and Times even are seq0, Times odd is seq1
+    let start = unsafe { pwm.task_start_seq0() };
+    let stop = unsafe { pwm.task_stop() };
+
+    let mut ppi = Ppi::new_one_to_one(p.PPI_CH1, button1.event_in(), start);
+    ppi.enable();
+
+    let mut ppi2 = Ppi::new_one_to_one(p.PPI_CH0, button2.event_in(), stop);
+    ppi2.enable();
+
+    info!("PPI setup!");
+    info!("Press button 1 to start LED 1");
+    info!("Press button 2 to stop LED 1");
+    info!("Note! task_stop stops the sequence, but not the pin output");
+
+    // Block forever so the above drivers don't get dropped
+    pending::<()>().await;
+}