Add HIC docs

docs/hic/README.md

@@ -13,3 +13,4 @@
 | [nrf52820](nrf52820.md)       |  M4  |  64 MHz |  32 KB | 256 KB |  FS |
 | [sam3u2c](sam3u2c.md)         |  M3  |  96 MHz |  32 KB | 128 KB |  HS |
 | [stm32f103xb](stm32f103xb.md) |  M3  |  72 Mhz |  20 KB | 128 KB |  FS |
+| [stm32g431xb](stm32g431xb.md) |  M4  | 170 Mhz |  32 KB | 128 KB |  FS |

docs/hic/stm32g431xb.md

@@ -0,0 +1,38 @@
+# stm32g431xb HIC
+
+Based on STM32G431CBT6 chip ([Datasheet](https://www.st.com/resource/en/datasheet/stm32g431cb.pdf)).
+
+- Cortex-M4 170 Mhz
+- 128 KB Flash
+- 32 KB RAM
+- USB 2.0 full-speed interface with LPM and BCD support.
+
+## Memory Map
+
+| Region   |  Size  | Start       | End         |
+|----------|--------|-------------|-------------|
+| Flash    | 128 KB | 0x0800_0000 | 0x0002_0000 |
+| SRAM     | 32 KB  | 0x2000_0000 | 0x2000_8000 |
+
+Bootloader size is 46 KB
+
+## DAPLink default pin assignment
+
+| Signal      | I/O | Symbol  | Pin |
+|-------------|:---:|---------|:---:|
+| SWD / JTAG  |
+| SWCLK / TCK |  O  | PB13    |  27 |
+| SWDIO / TMS |  O  | PB14    |  28 |
+| SWDIO / TMS |  I  | PB12    |  26 |
+| SWO / TDO   |  I  | PA10    |  32 |
+| nRESET      |  O  | PB0     |  16 |
+| UART        |
+| UART RX     |  I  | PA2     |  10 |
+| UART TX     |  O  | PA3     |  11 |
+| Button      |
+| NF-RST But. |  I  | PB15    |  29 |
+| LEDs        |
+| Connect. LED|  O  | PB6     |  43 |
+| HID LED     |  O  | PA9     |  31 |
+| CDC LED     |  O  | PA8     |  30 |
+| MSC LED     |  O  | PB11    |  25 |