Adafruit Feather nRF52840 Express - onboard neopixel not working

[jmhobbs]

I've got a Feather nRF23840 Express with the built in neopixel that I can not make light with ws2812.

I don't believe I have anything wrong in my code.

package main

import (
  "image/color"
  "machine"
  "time"

  "tinygo.org/x/drivers/ws2812"
)

var neo machine.Pin

func main() {
  neo = machine.WS2812
  neo.Configure(machine.PinConfig{Mode: machine.PinOutput})

  ws := ws2812.NewWS2812(neo)
  time.Sleep(500 * time.Millisecond)
  for {
    ws.WriteColors([]color.RGBA{{255, 0, 0, 255}})
    time.Sleep(2500 * time.Millisecond)

    ws.WriteColors([]color.RGBA{{0, 255, 0, 255}})
    time.Sleep(2500 * time.Millisecond)

    ws.WriteColors([]color.RGBA{{0, 0, 255, 255}})
    time.Sleep(2500 * time.Millisecond)
  }
}

I can not find a reference now, but I thought I saw that this board used a WS2812B, and digging around I found that the timings on a B are different than rev A; datasheet adafruit reference code and thought perhaps that was the issue.

I grabbed the driver code and fiddled with the write intervals in an attempt to get it working but did not succeed. I think I understand what is happening in that codegen but I lack a lot of peripheral knowledge here.

It does work when using that Adafruit library and flashing from Arduino IDE.

Thanks!

[sago35]

I tried flashing your code onto the Feather nRF52840. It seems to be working correctly on my board.

[jmhobbs]

Well that's concerning, thank you for checking that @sago35.

I have another version where I also blink the machine.LED pin when I'm changing the neopixel and that works so I know it's flashing on and running OK, tinygo monitor works as well if I drop in println statements.

I will try asking over on the Adafruit support forums for ideas. I would suspect bum hardware but it operates fine from C++ so I'm lost.

[aykevl]

Did you manage to figure out the issue? One thing you could try is to disable interrupts while writing. Something like:

import "runtime/interrupt"

// inside the loop
mask := interrupt.Disable()
ws.WriteColors([]color.RGBA{{0, 0, 255, 255}})
interrupt.Restore(mask)

(Closing for now, this doesn't appear to be a bug but feel free to comment if it's still a problem).