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qmk_firmware/docs/platformdev_proton_c.md
Joel Challis 345e19f691
Add converter docs (#17593)
2022-07-08 22:49:16 +01:00

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Proton C

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

Proton C

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.