KeyBoard_QT/docs/firmware_proto_transport.md

Firmware Proto Transport

Goal

Add CDC and GATT private communication without rewriting the existing keyboard, time, theme, and LED business logic.

The firmware side should:

• keep standard HID behavior for normal keys
• receive host commands over CDC and GATT
• report private state and function key events over CDC and GATT
• reuse existing modules where possible

Completed Nodes

Node 1: internal function events

Files:

• src/events/function_bitmap_event.h
• src/events/function_bitmap_event.c
• src/events/function_key_event.h
• src/events/function_key_event.c

Design notes:

• function_bitmap_event carries the 29-byte function bitmap from host
• function_key_event carries usage + action when a configured function key is pressed or released
• these events isolate transport modules from keyboard internals

Planned next nodes

• keyboard split logic uses function_bitmap_event
• CDC transport module
• GATT transport module
• nanopb integration and generated protocol code

Node 2: keyboard split point

Files updated in this step:

• src/modules/keyboard_module.c

Design notes:

• reuse the existing keymap and HID path
• add one explicit split point before HID submission
• keep normal keys on HID
• send configured function keys to private transport only

Implemented behavior:

• store the 29-byte function bitmap
• for keyboard usages marked as function keys:
  • stop normal HID reporting
  • emit function_key_event
• for consumer usages marked as function keys:
  • stop normal HID reporting
  • emit function_key_event