CircuitBrains

Deluxe

https://kevinneubauer.com/projects/circuitbrains-deluxe/

Small form-factor 48-pin castellated pad module. Designed to allow an easy implementation of CircuitPython in maker/hacker projects without the bulk of a large breakout board.

Specs:

• Atmel ATSAMD51J19A Microcontroller (32-bit ARM Cortex M4)
• 8 MB SPI Flash
• Onboard 3.3V LDO Regulator
• Power and Status LEDs
• Breakouts for SPI and I2C
• Breakouts for 13 Analog and 19 Digital Inputs/Outputs

Revision History / Known Issues:

v1.0:

• Initial release
• Analog output does no work due to silicon issue with ATSAMD51. Requires a dedicated VREF/AREF pin with external 3.3 VREF input

v1.1 & v1.2:

• Not released due to issues resulting from design changes. I removed the pull-up on RST because the datasheet says it was optional. Turns out it was not so optional. These revisions will not function without a 10K resistor bodged onto the RST line.
• Dedicated a pin to VREF. Added a 0 Ohm resistor with a 3.3v input into VREF.
• Switched from 4 layer to 2 layer board layout
• Rearranged layout to allow for pad documentation
• Added silkscreen for pad/pin assignments
• Added logo
• Removed inductor on VSW. Board will only work on linear power mode due to this.
• Removed polyfuse. Acceptable risk tradeoff for the space. If you want a fuse, add it to your design that incorporates this board.
• Removed Schottkey diode on VIN. Acceptable risk tradeoff for the space.
• Changed to a different flash chip with a smaller footprint
• Shuffled I/O pin assignments for more efficient trace routing/layout

v1.3:

• Added 10k pull-up back to RST.
• All tests working out: I2C, SPI, Analog & Digital In, Analog Out

Basic

https://kevinneubauer.com/projects/circuitbrains-basic/

Small form-factor 28-pin castellated pad module. Designed to allow an easy implementation of CircuitPython in maker/hacker projects without the bulk of a large breakout board.

Specs:

• Atmel ATSAMD21E18A Microcontroller (32-bit ARM Cortex M0)
• 4 MB SPI Flash
• Onboard 3.3V LDO Regulator
• Power and Status LEDs
• Breakouts for SPI and I2C
• Breakouts for 4 Analog and 8 Digital Inputs/Outputs

Revision History / Known Issues: v1.2:

• Initial Release
• All tests working out