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Markus Koch 632772d4b7 Document WS2812B level shifter erratum
2021-07-17 23:07:24 +02:00
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README.MD Document WS2812B level shifter erratum 2021-07-17 23:07:24 +02:00

README.MD

WS2812B light signal - CPU Board

Board to run colorchord2 on a string of WS2812B LEDs with live line-in audio.

Errata (Rev 01)

  • Opamp inverting / non-inverting inputs are swapped
    • Workaround: Lift pads 2 and 3, and 5 and 6, and connect them crossed using magnet wire.
  • Opamp is not rail-to-rail and does not allow to use the ADC in full range
    • Workaround: Only use limited range -640 to 520.
  • LED footprint is wrong.
    • Workaround: Flip 180 degrees and solder shifted onto the right pads, then use magnet wire to connect the remaining two pads.
  • Serial boot loader non-functional (uses incompatible UART I/Os).
    • Workaround: Program via JTAG / SWD.
  • Missing level shifters for WS2812B LEDs (RX)
    • Workaround: Don't use WS2812B RX inputs on the board
  • Missing level shifters for WS2812B LEDs (TX)
    • Workaround: The first LED will kinda sorta do the level shifting for you, but sometimes fail to display correctly. Just ignore its erratic blinking.