The Arducompute MCU board specs:
- If the MCU does not support a certain interface, then the corresponding pins must not be populated for that interface.
- The listed interfaces in the Arducompute pin mappings can also support other interfaces or be used as GPIO. For example, the SPI pins must support SPI, but the carrier board can use then as GPIO and the MCU board can have them support other things as well
- All voltage regulation for the MCU must be on the MCU board
- Only the MCU and support circuitry is allowed on the MCU board. No other peripherals should be placed, with the exception of USB support hardware and RAM
- The boot ROM pins are only to be used for ROMLESS MCUs, not as a general purpose SPI port
- VIN pins can be used as power input or a power on signal. If used as power on, there must be an onboard always-on jumper
- Must have 5V input and 3v output
- IO can be 3.3V or 5V
Carrier board specs:
- All level shifting must be done on the carrier board if simultaneous 3v and 5v compatibility is desired
- Power can be supplied through 5V or VIN or both
- Reset line must have a pull up resistor
- 3V Out is output only
I have completed two beta boards, both ATMEGA328 based. I also have a board in development that is STM32 based. The final designs are almost done, I just need to verify all the bugs are out. As far as carrier boards go I only have a basic breakout board so far. Once all bugs have been worked out, I will release gerber files for the boards so you can make your own. I am also considering selling premade boards if you don't want / can't solder smd components. More to come very soon!