No LEDs / No Midi Out? [RESOLVED]

Midipal is completed. The firmware seems to be intact. I can access the apps. Monitor shows incoming midi data, but I’m not getting the LEDs to light and I don’t think I’m sending any midi data out.


I may have the LEDs in backwards (I couldn’t see the green dots) but maybe it’s something more serious since I may have a problem with output.

How should I methodically begin to test this? Reverse an LED first?

One thing which is important to note is that the LED and the MIDI in/out circuitry are two independent things…

When the MCU writes data to the MIDI out, it also blinks the OUT LED. When the MCU acknowledges incoming MIDI data, it blinks the IN LED. which means that the MIDI in / out might be perfectly OK even if the LEDs are not blinking. Reversely, the MIDI out LED might be blinking but the MIDI out circuitry could be kaput.

So please check first if your problem is related to the MIDI in / out, or if it is related to the LEDs.

  • With the monitor app, do you see on the screen incoming MIDI messages?
  • With the monitor app, does the IN LED blink?
  • With the ear training game app, does the OUT LED blink?
  • With the ear training game app, are there notes sent to the MIDI out?

Eh… it was predictable.

I reversed the LEDs which I fixed. I was lucky not to have pulled the complete pad off of one of them. Works okay.

I may have had a tiny solder bridge on 15-16 of the MCU which is MISO/MOSI right?

Anyway I cleaned that up a bit too and now it’s working fine. I’ve got the arpeggiator making arpeggios and der blinkenlights are blinken.

Sorry to have bothered you!