Sprocket Boards

This is a breakout board for the STM32G031. Each board is 15.0x47.0mm.

Each board costs under 2.00 EUR/ea at 100 units.

I documented the design process here:

A design process story in 4 pictures, from concept to board. I'm still waiting on the boards to arrive (looks like they'll be done being built tomorrow hopefully), but I thought I would wax nostalgic about how my process worked for this.

Read along for more details. 1/? pic.twitter.com/6kHYOADmBB

— James Munns (@bitshiftmask) March 15, 2021

And streamed most of the original design on YouTube here:

The Board

It has:

• A 28-pin STM32G031
  • 64MHz Cortex M0+
  • 8KiB RAM
  • 64KiB Flash
• Two WS2812b-style Smartleds
• Two User buttons
• Reverse Protection Diode
• One Power LED (always on)
• Two User LEDs
• 3.3v LDO
• Four QWIIC connectors
• Three main connectors:
  • One with 8 GPIOs, all with PWM, six with ADC channels and Power
  • One with I2C, SPI, UART, and Power
  • One with SWD connectors, reset pin, and power

The board is meant to be brick mount compatible, and is the same size as a LEGO 2x6 Plate.

The four mounting pins each electrically connect to:

• +5V0
• Ground
• SDA (3v3)
• SCL (3v3)

These connectors are intended for use with a testing, programming, or configuration jig.

Compatible Add-On Boards

I don't know if I'll make a lot of accessories, but I'll certainly make some.

Clink board

This board is intended to take PWM as inputs (on up to eight channels). The PWM signal is buffered by a TI 74HC244D, and sent through an RC circuit, taken from the Raspberry Pi 3B+ Audio.

I don't expect Hi-Fi audio, but might be useful to make appropriate bleep-bloops.

The board also contains it's own 5V LDO to reduce signal noise.