STeMCell V1 STM32 Pro Micro Controller

STeMCell STM32 Pro Micro Controller

The STeMCell is a powerful Pro Micro replacement based on a fast STM32F411 Arm chip with plenty of memory

Warning: This is a STemCell controller V1, not the latest version V2.

Features

• Pinout compatible with the classic Pro Micro with additional 5 I/O pins along the bottom edge
• Powerful STM32F411 Arm microcontroller clocked at 100 MHz with 128 KB SRAM and 512 KB of flash
• 21 GPIO pins (3.3 V logic instead of 5 V)
• Only 4 mm thick thanks to a partially mid-mounted USB-C socket
• Effortless drag & drop flashing (TinyUF2 bootloader)
• Includes standard header pins (2x 12 pin)

Flashing QMK

QMK for any Pro Micro based keyboard can be built and flashed by simply adding an extra argument to the command line:

qmk flash -kb crkbd -km default -e CONVERT_TO=stemcell

Depending on which pin is used for the split communication, you might need to add another argument:

D0: Not needed
D1: -e STMC_IS=yes
D2: Not needed
D3: -e STMC_US=yes

For split keyboards to work correctly some pins might also need to be configured by closing PCB jumpers on the back of the PCB:

TX0: F
RX0: F
SDA: N
SCL: N
TX PUp: A2