[Controller] Added board config for custom controller STeMCell (#16287)

Co-authored-by: Mariappan Ramasamy <947300+Mariappan@users.noreply.github.com>
Co-authored-by: Mariappan Ramasamy <maari@basis-ai.com>
Co-authored-by: Sadek Baroudi <sadekbaroudi@gmail.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/docs/feature_converters.md b/docs/feature_converters.md
index 569cf0f17d..936ab44559 100644
--- a/docs/feature_converters.md
+++ b/docs/feature_converters.md
@@ -15,6 +15,7 @@ Currently the following converters are available:
 | `promicro` | `promicro_rp2040` |
 | `promicro` | `blok`            |
 | `promicro` | `bit_c_pro`       |
+| `promicro` | `stemcell`        |
 
 See below for more in depth information on each converter.
 
@@ -56,6 +57,7 @@ If a board currently supported in QMK uses a [Pro Micro](https://www.sparkfun.co
 | [SparkFun Pro Micro - RP2040](https://www.sparkfun.com/products/18288) | `promicro_rp2040` |
 | [Blok](https://boardsource.xyz/store/628b95b494dfa308a6581622)         | `blok`            |
 | [Bit-C PRO](https://nullbits.co/bit-c-pro)                             | `bit_c_pro`       |
+| [STeMCell](https://github.com/megamind4089/STeMCell)                   | `stemcell`        |
 
 Converter summary:
 
@@ -66,6 +68,7 @@ Converter summary:
 | `promicro_rp2040` | `-e CONVERT_TO=promicro_rp2040` | `CONVERT_TO=promicro_rp2040` | `#ifdef CONVERT_TO_PROMICRO_RP2040` |
 | `blok`            | `-e CONVERT_TO=blok`            | `CONVERT_TO=blok`            | `#ifdef CONVERT_TO_BLOK`            |
 | `bit_c_pro`       | `-e CONVERT_TO=bit_c_pro`       | `CONVERT_TO=bit_c_pro`       | `#ifdef CONVERT_TO_BIT_C_PRO`       |
+| `stemcell`        | `-e CONVERT_TO=stemcell`        | `CONVERT_TO=stemcell`        | `#ifdef CONVERT_TO_STEMCELL`        |
 
 ### Proton C :id=proton_c
 
@@ -99,3 +102,22 @@ The following defaults are based on what has been implemented for [RP2040](platf
 ### SparkFun Pro Micro - RP2040, Blok, and Bit-C PRO :id=promicro_rp2040 
 
 Currently identical to  [Adafruit KB2040](#kb2040).
+
+### STeMCell :id=stemcell
+
+Feature set currently identical to [Proton C](#proton_c).
+There are two versions of STeMCell available, with different pinouts:
+  - v1.0.0
+  - v2.0.0 (pre-release v1.0.1, v1.0.2)
+Default official firmware only supports v2.0.0 STeMCell.
+
+STeMCell has support to swap UART and I2C pins, to enable single-wire uart communication in STM chips.
+
+The following additional flags has to be used while compiling, based on the pin used for split communication.
+
+| Split Pin | Compile flags |
+|-----------|---------------|
+| D3        | -e STMC_US=yes|
+| D2        | Not needed    |
+| D1        | -e STMC_IS=yes|
+| D0        | Not needed    |