View schematic (github) 

core-descriptionADC1 (MCP3208):

  • SPI Connection: MOSI (PA7), MISO (PA6), SCK (PA5), CS2 (PA3)
  • voltage input: 0-3,3V (used for reading potentiometers)

ADC2 (MCP3208): 

  • SPI Connection: MOSI (PA7), MISO (PA6), SCK (PA5), CS1 (PA2)
  • the op-amp part before ADC2 scales +/-5V down to 0-3,3V

TRIMMER R3, R11: fine tune for audio out

TRIMMER R32, R33: fine tune for audio in

Power supply info:

  • Method 1: The Axoloti will be powered directly by the 7805 voltage output and the +12V from Eurorack will be activate the VBUS send input (3,3V). Don’t use the USB host function of axoloti core.
  • Method 2: Connect the Axoloti core power supply part to the pinouts of the Euxoloti PCB (JP1). This will be the safe way because the original Axoloti voltage regulation has many protection functions (soft start, overheating protection etc.)


Extra header row (JP4), to connect more things to axoloti’s pinouts


Control PCB


more infos soon…