qmk/docs/proton_c_conversion.md

Converting a board to use the Proton C

Since the Proton C is a drop-in replacement for a Pro Micro we've made it easy to use. This page documents a handy automated process for converting keyboards, as well as documenting the manual process if you'd like to make use of Proton C features that aren't available on Pro Micros.

Automatic Conversion

If a board currently supported in QMK uses a Pro Micro (or compatible board) and you want to use the Proton C, you can generate the firmware by appending CONVERT_TO_PROTON_C=yes (or CTPC=yes) to your make argument, like this:

make 40percentclub/mf68:default CTPC=yes

You can add the same argument to your keymap's rules.mk, which will accomplish the same thing.

This exposes the CONVERT_TO_PROTON_C flag that you can use in your code with #ifdefs, like this:

#ifdef CONVERT_TO_PROTON_C
    // Proton C code
#else
    // Pro Micro code
#endif

If you get errors about PORTB/DDRB, etc not being defined, so you'll need to convert the keyboard's code to use the GPIO Controls that will work for both ARM and AVR. This shouldn't affect the AVR builds at all.

The Proton C only has one on-board LED (C13), and by default, the TXLED (D5) is mapped to it. If you want the RXLED (B0) mapped to it instead, add this like to your config.h:

#define CONVERT_TO_PROTON_C_RXLED

Feature Conversion

These are defaults based on what has been implemented for ARM boards.

Feature	Notes
Audio	Enabled
RGB Lighting	Disabled
Backlight	Forces task driven PWM until ARM can provide automatic configuration
USB Host (e.g. USB-USB converter)	Not supported (USB host code is AVR specific and is not currently supported on ARM)
Split keyboards	Partial - heavily dependent on enabled features

Manual Conversion

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

MCU = STM32F303

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.