Find a timing that works with WS2815

hello_gradient/src/bin/blazing.rs

@@ -0,0 +1,26 @@
+#![no_std]
+#![no_main]
+
+use core::iter::repeat;
+use lights::{
+    gamma::GammaCorrector,
+    PixelIterator,
+    rgb::{
+        gray
+    }
+};
+use lights_hal::{boot, delay, entry};
+
+#[entry]
+fn main() -> ! {
+    let mut lights = GammaCorrector(boot());
+
+    let mut pattern = repeat(gray(0)).take(15).chain(repeat(gray(255)).take(15)).cycle();
+
+    loop {
+        pattern.clone().take(125).render_to(&mut lights);
+
+        pattern.next();
+        delay(1_000_000);
+    }
+}

itsybitsy_m0_lights/src/lib.rs

@@ -31,27 +31,33 @@ pub fn boot() -> impl Lights<Pixel = HardwareRgb> {
     let mut pins = hal::Pins::new(peripherals.PORT);
 
     NeopixelLights {
-        out: pins.d7.into_push_pull_output(&mut pins.port)
+        out: pins.d7.into_push_pull_output(&mut pins.port),
+        high_out: pins.d5.into_push_pull_output(&mut pins.port),
     }
 }
 
+// WS2815 lighting times
 // approx. 20ns per clock cycle;
-const ZERO_HIGH_CYCLES: u32 = 11; // smidge above 200ns
+const ZERO_HIGH_CYCLES: u32 = 8; // about 160ns
+const ZERO_LOW_CYCLES: u32 = 42; // about 840ns
 const ONE_HIGH_CYCLES: u32 = 35; // about 700ns
-const DATA_LOW_CYCLES: u32 = 25; // about 500ns
-const LATCH_CYCLES: u32 = 300; // about 6000ns
+const ONE_LOW_CYCLES: u32 = 15; // about 300ns
+const LATCH_CYCLES: u32 = 15000; // about 300us
 
-pub struct NeopixelLights<T: OutputPin> {
-    out: T
+pub struct NeopixelLights<T: OutputPin, U: OutputPin> {
+    out: T,
+    high_out: U
 }
 
-impl<T: OutputPin> NeopixelLights<T> {
+impl<T: OutputPin, U: OutputPin> NeopixelLights<T, U> {
     #[inline]
     fn write(&mut self, bit: bool) {
         self.out.set_high();
+        self.high_out.set_high();
         delay(if bit { ONE_HIGH_CYCLES } else { ZERO_HIGH_CYCLES });
         self.out.set_low();
-        delay(DATA_LOW_CYCLES);
+        self.high_out.set_low();
+        delay(if bit { ONE_LOW_CYCLES } else { ZERO_LOW_CYCLES });
     }
 
     #[inline]
@@ -67,7 +73,7 @@ impl<T: OutputPin> NeopixelLights<T> {
     }
 }
 
-impl<T: OutputPin> Lights for NeopixelLights<T> {
+impl<T: OutputPin, U: OutputPin> Lights for NeopixelLights<T, U> {
     type Pixel = HardwareRgb;
 
     #[inline]