wendallsan / song-naga-2cock Goto Github PK

Behavior:

When the Daisy Seed is plugged into the PCB, it is not available to USB. The program appears to run, and the Daisy Seed appears to run when powered only by Eurorack power.

per @nick on Daisy Seed Discord:

the onboard USB chip could be getting starved if one of the 3V3 output pins is shorted.

I reviewed the 3V3_A pin: connects to all 18 of the ADC-connected pots and the MCP6001. There is about 5.5k resistance between 3V3_A and ground (not sure if this is a short or not).

per @squarewolf on Daisy Seed Discord:

hmm, that's odd... I did a quick search on github and found this: https://github.com/electro-smith/Hardware/blob/master/reference/daisy_seed/Datasheet.md#pin-38---3v3-digital It says "Maximum 500mA total combined with MCU/RAM." for the digital 3V3 pin and "Maximum 150mA combined with onboard-AK4556 and Analog section of MCU." for the Analog 3V3 pin. Not sure what the CMU/RAM and the AK4556 and Analog section consume, but at least it's a ballpark...

TODO: look at the 3V3_D pin also and see if it is shorted.
TODO: measure the current of these pins to see if they exceed 500mV.

Per @corvus Prudens on the Daisy Seed Discord:

I'd be careful with the muxed CVs: the cutoff on the op amp circuit is around 600 Hz, which means your sampling period for each signal needs to be more like 100Hz or less. You'll get crosstalk between the signals if you switch between them too fast.

I'd take the capacitor (C15) from 10 nF down to 1 if you want to sample the inputs at something like 1kHz.