47aeab152f
Demonstrates how to set the colour of a WS2812B to blue using PWM, and the use of multiple sequences along with their own config. This required an API change.
61 lines
2.0 KiB
Rust
61 lines
2.0 KiB
Rust
#![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 defmt::*;
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use embassy::executor::Spawner;
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use embassy::time::{Duration, Timer};
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use embassy_nrf::gpio::NoPin;
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use embassy_nrf::pwm::{
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Config, Prescaler, SequenceConfig, SequenceLoad, SequenceMode, SequencePwm,
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};
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use embassy_nrf::Peripherals;
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// WS2812B LED light demonstration. Drives just one light.
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// The following reference on WS2812B may be of use:
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// https://cdn-shop.adafruit.com/datasheets/WS2812B.pdf
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// In the following declarations, setting the high bit tells the PWM
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// to reverse polarity, which is what the WS2812B expects.
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const T1H: u16 = 0x8000 | 13; // Duty = 13/20 ticks (0.8us/1.25us) for a 1
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const T0H: u16 = 0x8000 | 7; // Duty 7/20 ticks (0.4us/1.25us) for a 0
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const RES: u16 = 0x8000;
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// Provides data to a WS2812b (Neopixel) LED and makes it go blue. The data
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// line is assumed to be P1_05.
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#[embassy::main]
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async fn main(_spawner: Spawner, p: Peripherals) {
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// Declare the bits of 24 bits
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let mut blue_seq: [u16; 8 * 3] = [
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T0H, T0H, T0H, T0H, T0H, T0H, T0H, T0H, // G
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T0H, T0H, T0H, T0H, T0H, T0H, T0H, T0H, // R
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T1H, T1H, T1H, T1H, T1H, T1H, T1H, T1H, // B
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];
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let reset_seq = [RES; 1];
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let mut config = Config::default();
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config.sequence_load = SequenceLoad::Common;
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config.prescaler = Prescaler::Div1;
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config.max_duty = 20; // 1.25us (1s / 16Mhz * 20)
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let mut pwm = unwrap!(SequencePwm::new(
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p.PWM0, p.P1_05, NoPin, NoPin, NoPin, config,
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));
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let blue_seq_config = SequenceConfig::default();
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let mut reset_seq_config = SequenceConfig::default();
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reset_seq_config.end_delay = 799; // 50us (20 ticks * 40) - 1 tick because we've already got one RES
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unwrap!(pwm.start(
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&blue_seq,
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blue_seq_config,
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Some(&reset_seq),
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Some(reset_seq_config),
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SequenceMode::Times(2)
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));
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Timer::after(Duration::from_millis(20000)).await;
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info!("Program stopped");
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}
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