Document the Proton C pins for manual Pro Micro conversion (#7043)

1 files changed, 63 insertions, 6 deletions

diff --git a/docs/proton_c_conversion.md b/docs/proton_c_conversion.md
index dc0a3f4849..98f1508a9e 100644
--- a/docs/proton_c_conversion.md
+++ b/docs/proton_c_conversion.md
@@ -1,5 +1,9 @@
 # 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
@@ -8,13 +12,15 @@ You can add the same argument to your keymap's `rules.mk`, which will accomplish
 
 This exposes the `CONVERT_TO_PROTON_C` flag that you can use in your code with `#ifdef`s, like this:
 
-    #ifdef CONVERT_TO_PROTON_C
-        // Proton C code
-    #else
-        // Pro Micro code
-    #endif
+```c
+#ifdef CONVERT_TO_PROTON_C
+    // Proton C code
+#else
+    // Pro Micro code
+#endif
+```
 
-Before being able to compile, you may get some errors about `PORTB/DDRB`, etc not being defined, so you'll need to convert the keyboard's code to use the [GPIO Controls](internals_gpio_control.md) that will work for both ARM and AVR. This shouldn't affect the AVR builds at all.
+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](internals_gpio_control.md) 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`:
 
@@ -31,3 +37,54 @@ These are defaults based on what has been implemented for ARM boards.
 | [Backlight](feature_backlight.md)   | Forces [task driven PWM](feature_backlight.md#software-pwm-driver) 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](feature_split_keyboard.md) | Not supported yet                                                                                       |
+
+## 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 <sup>1</sup> |
+| `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` <sup>2</sup> | | `C13` <sup>2</sup> | `D5` (TX LED) |
+
+You can also make use of several new pins on the extended portion of the Proton C:
+
+| Left | | Right | 
+|------|-|-------|
+| `A4`<sup>3</sup> | | `B10` |
+| `A5`<sup>4</sup> | | `B11` |
+| `A6` | | `B12` |
+| `A7` | | `A14`<sup>5</sup> (SWCLK) |
+| `A8` | | `A13`<sup>5</sup> (SWDIO) |
+| `A15` | | RESET<sup>6</sup> |
+
+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.