qmk_firmware/platformdev_proton_c.md

Proton C

The Proton C is an Arm STM32F303xC based drop-in replacement for the Pro Micro.

Features

• Through-hole mounted USB-C Port
• 32-bit 72MHz Cortex-M4 processor (STM32F303CCT6)
• I2C, SPI, PWM, DMA, DAC, USART, I2S
• 23x 3.3V I/O Ports
• 1x 5V output for WS2812 LED chains
• 256kB flash
• 40kB RAM
• AST1109MLTRQ speaker footprint
• Reset button

Warnings

Some of the PCBs compatible with Pro Micro have VCC (3.3V) and RAW (5V) pins connected (shorted) on the pcb. Using the Proton C will short 5V power from USB and regulated 3.3V which is connected directly to the MCU. Shorting those pins may damage the MCU on the Proton C.

So far, it appears that this is only an issue on the Gherkin PCBs, but other PCBs may be affected in this way.

In this case, you may want to not hook up the RAW pin at all.

Manual Conversion

To use the Proton C natively, without having to specify CONVERT_TO=proton_c, you need to change the MCU line in rules.mk:

MCU = STM32F303
BOARD = QMK_PROTON_C

Remove these variables if they exist:

• BOOTLOADER
• EXTRA_FLAGS

Finally convert all pin assignments in config.h to the stm32 equivalents.

Pro Micro Left	Proton C Left		Proton C Right	Pro Micro Right
D3	A9		5v	RAW (5v)
D2	A10		GND	GND
GND	GND		FLASH	RESET
GND	GND		3.3v	VCC 1
D1	B7		A2	F4
D0	B6		A1	F5
D4	B5		A0	F6
C6	B4		B8	F7
D7	B3		B13	B1
E6	B2		B14	B3
B4	B1		B15	B2
B5	B0		B9	B6
B0 (RX LED)	C13 2		C13 2	D5 (TX LED)

You can also make use of several new pins on the extended portion of the Proton C:

Left		Right
A43		B10
A54		B11
A6		B12
A7		A145 (SWCLK)
A8		A135 (SWDIO)
A15		RESET6

Notes:

1. On a Pro Micro VCC can be 3.3v or 5v.
2. A Proton C only has one onboard LED, not two like a Pro Micro. The Pro Micro has an RX LED on D5 and a TX LED on B0.
3. A4 is shared with the speaker.
4. A5 is shared with the speaker.
5. A13 and A14 are used for hardware debugging (SWD). You can also use them for GPIO, but should use them last.
6. Short RESET to 3.3v (pull high) to reboot the MCU. This does not enter bootloader mode like a Pro Micro, it only resets the MCU.