2026-04-11 11:43:45 +08:00
|
|
|
# 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
|
|
|
|
|
|
2026-04-11 11:46:56 +08:00
|
|
|
### 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`
|
2026-04-11 11:56:45 +08:00
|
|
|
|
|
|
|
|
### Node 3: nanopb build integration and protocol core
|
|
|
|
|
|
|
|
|
|
Files updated in this step:
|
|
|
|
|
|
|
|
|
|
- `CMakeLists.txt`
|
|
|
|
|
- `prj.conf`
|
|
|
|
|
- `app.overlay`
|
|
|
|
|
- `inc/keyboard_proto.h`
|
|
|
|
|
- `src/modules/keyboard_proto.c`
|
|
|
|
|
|
|
|
|
|
Design notes:
|
|
|
|
|
|
|
|
|
|
- use NCS built-in nanopb instead of a hand-written protobuf runtime
|
|
|
|
|
- generate protocol code from the shared `.proto`
|
|
|
|
|
- keep one firmware-side protocol helper that:
|
|
|
|
|
- encodes and decodes `CdcPacketBody`
|
|
|
|
|
- encodes and decodes `CdcFrame`
|
|
|
|
|
- validates checksum
|
|
|
|
|
- routes host commands back into existing modules
|
|
|
|
|
|
|
|
|
|
Implemented behavior:
|
|
|
|
|
|
|
|
|
|
- enable CDC ACM class in Zephyr USB device-next stack
|
|
|
|
|
- add a CDC ACM UART node in devicetree
|
|
|
|
|
- wire `zephyr_nanopb_sources()` into the build
|
|
|
|
|
- add protocol helper functions for:
|
|
|
|
|
- body encode/decode
|
|
|
|
|
- CDC frame encode
|
|
|
|
|
- CDC frame stream extraction
|
|
|
|
|
- hello response build
|
|
|
|
|
- ack/error build
|
|
|
|
|
- function key event build
|
|
|
|
|
- LED state build
|
|
|
|
|
- host command dispatch
|
|
|
|
|
|
|
|
|
|
## Planned next nodes
|
|
|
|
|
|
|
|
|
|
- CDC transport module
|
|
|
|
|
- GATT transport module
|
