157 lines
4.2 KiB
Rust
157 lines
4.2 KiB
Rust
#![no_std]
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#![feature(asm)]
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extern crate cortex_m;
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extern crate embedded_hal;
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extern crate itsybitsy_m0 as hal;
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extern crate panic_halt;
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pub use cortex_m::asm::delay;
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pub use hal::entry;
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use core::fmt::Debug;
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use core::sync::atomic::{compiler_fence, Ordering};
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use core::u8;
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pub use embedded_hal::digital::v2::OutputPin;
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use hal::{clock::GenericClockController, pac::Peripherals};
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use lights::{HardwareRgb, Lights};
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pub fn boot() -> NeopixelLights<
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impl OutputPin<Error = ()>,
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impl OutputPin<Error = ()>,
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impl OutputPin<Error = ()>,
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> {
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let mut peripherals = Peripherals::take().unwrap();
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let _clock = GenericClockController::with_internal_32kosc(
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peripherals.GCLK,
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&mut peripherals.PM,
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&mut peripherals.SYSCTRL,
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&mut peripherals.NVMCTRL,
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);
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let mut pins = hal::Pins::new(peripherals.PORT);
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NeopixelLights {
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out: pins.d7.into_push_pull_output(&mut pins.port),
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high_out: pins.d5.into_push_pull_output(&mut pins.port),
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red_led: pins.d13.into_open_drain_output(&mut pins.port),
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debug_light: false,
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}
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}
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// WS2815 ideal lighting times
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// approx. 20ns per clock cycle;
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// const ZERO_HIGH_CYCLES: u32 = 11; // about 220ns
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// const ONE_HIGH_CYCLES: u32 = 29; // about 580ns
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// const ZERO_LOW_CYCLES: u32 = 29; // about 580ns
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// const ONE_LOW_CYCLES: u32 = 11; // about 220ns
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const LATCH_CYCLES: u32 = 15000; // about 300us
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pub struct NeopixelLights<T: OutputPin, U: OutputPin, V: OutputPin> {
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pub out: T,
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pub high_out: U,
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pub red_led: V,
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pub debug_light: bool,
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}
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impl<T: OutputPin, U: OutputPin, V: OutputPin> NeopixelLights<T, U, V>
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where
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T::Error: Debug,
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U::Error: Debug,
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V::Error: Debug,
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{
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#[inline]
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pub fn write(&mut self, bit: bool) {
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// go high
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self.high_out.set_high().unwrap();
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// experimentally, there is some unknown overhead
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// but these timings appear to work for me
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unsafe {
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compiler_fence(Ordering::SeqCst);
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asm!(
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// 8 nops
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"nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;",
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);
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compiler_fence(Ordering::SeqCst);
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}
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if bit {
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unsafe {
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compiler_fence(Ordering::SeqCst);
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asm!(
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// 14 nops
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"nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;",
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"nop;", "nop;", "nop;", "nop;",
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);
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compiler_fence(Ordering::SeqCst);
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}
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}
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// go low
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self.high_out.set_low().unwrap();
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unsafe {
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compiler_fence(Ordering::SeqCst);
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asm!(
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// 15 nops
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"nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;", "nop;",
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"nop;", "nop;", "nop;", "nop;", "nop;",
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);
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compiler_fence(Ordering::SeqCst);
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}
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}
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#[inline]
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pub fn byte(&mut self, byte: u8) {
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self.write(byte & 0x80 != 0);
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self.write(byte & 0x40 != 0);
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self.write(byte & 0x20 != 0);
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self.write(byte & 0x10 != 0);
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self.write(byte & 0x08 != 0);
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self.write(byte & 0x04 != 0);
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self.write(byte & 0x02 != 0);
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self.write(byte & 0x01 != 0);
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unsafe {
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compiler_fence(Ordering::SeqCst);
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asm!(
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// 5 nops
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"nop;", "nop;", "nop;", "nop;", "nop;",
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);
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compiler_fence(Ordering::SeqCst);
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}
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}
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/// Blink light, probably to indicate a loop is still running
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pub fn heartbeat(&mut self) {
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if self.debug_light {
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self.red_led.set_low().unwrap();
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} else {
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self.red_led.set_high().unwrap();
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}
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self.debug_light = !self.debug_light;
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}
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}
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impl<T: OutputPin, U: OutputPin, V: OutputPin> Lights for NeopixelLights<T, U, V>
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where
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T::Error: Debug,
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U::Error: Debug,
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V::Error: Debug,
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{
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type Pixel = HardwareRgb;
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#[inline]
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fn render(&mut self, rgb: &HardwareRgb) {
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// GRB pixel order
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self.byte(rgb.1);
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self.byte(rgb.0);
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self.byte(rgb.2);
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}
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#[inline]
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fn latch(&mut self) {
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delay(LATCH_CYCLES);
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}
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}
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