2021-10-12 02:24:26 +02:00
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#![no_std]
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#![no_main]
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#![feature(type_alias_impl_trait)]
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#[path = "../example_common.rs"]
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mod example_common;
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use embassy::executor::Spawner;
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2022-02-26 08:15:37 +01:00
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use embassy::time::Duration;
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2021-10-12 02:24:26 +02:00
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use embassy_nrf::ppi::Ppi;
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2021-10-16 21:56:56 +02:00
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use embassy_nrf::saadc::{ChannelConfig, Config, Saadc, SamplerState};
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2021-10-12 02:24:26 +02:00
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use embassy_nrf::timer::{Frequency, Timer};
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use embassy_nrf::{interrupt, Peripherals};
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use example_common::*;
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// Demonstrates both continuous sampling and scanning multiple channels driven by a PPI linked timer
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#[embassy::main]
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async fn main(_spawner: Spawner, mut p: Peripherals) {
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let config = Config::default();
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let channel_1_config = ChannelConfig::single_ended(&mut p.P0_02);
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let channel_2_config = ChannelConfig::single_ended(&mut p.P0_03);
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let channel_3_config = ChannelConfig::single_ended(&mut p.P0_04);
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let mut saadc = Saadc::new(
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p.SAADC,
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interrupt::take!(SAADC),
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config,
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[channel_1_config, channel_2_config, channel_3_config],
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);
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2022-02-26 08:15:37 +01:00
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// We want the task start to effectively short with the last one ending so
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// we don't miss any samples. The Saadc will trigger the initial TASKS_START.
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let mut start_ppi = Ppi::new_one_to_one(p.PPI_CH0, saadc.event_end(), saadc.task_start());
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start_ppi.enable();
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2021-10-12 02:24:26 +02:00
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let mut timer = Timer::new(p.TIMER0);
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timer.set_frequency(Frequency::F1MHz);
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2022-02-26 08:15:37 +01:00
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timer.cc(0).write(1000); // We want to sample at 1KHz
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2021-10-12 02:24:26 +02:00
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timer.cc(0).short_compare_clear();
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2022-02-26 08:15:37 +01:00
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let mut sample_ppi =
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Ppi::new_one_to_one(p.PPI_CH1, timer.cc(0).event_compare(), saadc.task_sample());
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2021-10-12 02:24:26 +02:00
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timer.start();
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2022-02-26 08:15:37 +01:00
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// This delay demonstrates that starting the timer prior to running
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// the task sampler is benign given the calibration that follows.
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embassy::time::Timer::after(Duration::from_millis(500)).await;
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saadc.calibrate().await;
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let mut bufs = [[[0; 3]; 500]; 2];
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2021-10-15 08:44:23 +02:00
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let mut c = 0;
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let mut a: i32 = 0;
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2021-10-12 02:24:26 +02:00
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saadc
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.run_task_sampler(
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&mut bufs,
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|| {
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sample_ppi.enable();
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},
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move |buf| {
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// NOTE: It is important that the time spent within this callback
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// does not exceed the time taken to acquire the 1500 samples we
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// have in this example, which would be 10us + 2us per
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// sample * 1500 = 18ms. You need to measure the time taken here
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// and set the sample buffer size accordingly. Exceeding this
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// time can lead to the peripheral re-writing the other buffer.
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for b in buf {
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a += b[0] as i32;
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}
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c += buf.len();
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if c > 1000 {
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a = a / c as i32;
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info!("channel 1: {=i32}", a);
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c = 0;
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a = 0;
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}
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SamplerState::Sampled
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},
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)
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2021-10-12 02:24:26 +02:00
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.await;
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}
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