QMK Proton C

This article requires additional photographic illustration

Proton-C

Host port	USB Type C
Microcontroller	STM32F303CCT6
MPU	ARM Cortex-M4
Voltage	3.3V
Clock speed	72 MHz
I/O Voltage	3.3V, one +5V output pin
RAM	40 KB
Program memory	256 KB
Website	qmk.fm/proton-c/

The QMK Proton C is a microcontroller-board, pin-compatible with 3.3V Arduino Pro Micro. Instead of an 8-bit AVR, it uses the ARM Cortex-M4 based STM32F303CCT6 as microcontroller. It was made especially to be used with the QMK firmware.

Description

The USB port is a USB type C, which is both through-hole and SMD mounted. It should be tougher and not as easily torn off as the USB micro B port on the original Pro Micro.

The main part has pads for USB, a +5V output pin for WS2812 LED strips and a physical reset button.

The bottom is a break-away part with 11 additional digital I/O pins not on the Pro Micro and a hole and pad for a piezo speaker/buzzer.

Pinout

Function	Pin	↑	Pin	Function
		USB port
		(picture)
TX			5V
RX			GND
GND			DFU
GND			Vcc (+3.3V)
SDA	B7		A2
SCL	B6		A1
	B5		A0
	B4		A8
	B3		B13	SCLK
	B2		B14	MISO
	B1		B15	MOSI
	B0		B9
	A4		B10
	A5		B11
	A6		B12
	A7		A14	SWC
	A8		A13	SWD
	A15		NRST

• Internal pins: D+, D-, CR, A3 (5V)
• Pads on bottom: C14, C15, A3 (3.3V), BT0, C13 LED, RST, SWD, SWC
• Pads on top (breakaway part): Buzzer +, Buzzer -