https://github.com/headblockhead/slab-firmware
Firmware for the core boards of the Slab Keyboard system.
https://github.com/headblockhead/slab-firmware
c keyboard pico-sdk slab-keyboard tinyusb
Last synced: 8 days ago
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Firmware for the core boards of the Slab Keyboard system.
- Host: GitHub
- URL: https://github.com/headblockhead/slab-firmware
- Owner: headblockhead
- License: gpl-3.0
- Created: 2024-04-21T23:52:49.000Z (about 1 year ago)
- Default Branch: main
- Last Pushed: 2025-03-03T22:42:02.000Z (4 months ago)
- Last Synced: 2025-03-03T23:28:16.645Z (4 months ago)
- Topics: c, keyboard, pico-sdk, slab-keyboard, tinyusb
- Language: C
- Homepage:
- Size: 237 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# Slab Firmware
[](https://nixos.org) [](https://xcfile.dev)
The full firmware and downloads for the [Slab keyboard project](https://github.com/headblockhead/slab).
Downloads are in the releases section.
## Building
This project uses [Nix](https://nixos.org), run `nix develop` for a development environment, and `nix build` to build the firmware.
## Tasks
> [!IMPORTANT]
> You must be in the `nix develop` shell for these tasks to work!
### upload
Directory: ./build
Requires: build
Builds and uploads the firmware to the RP2040.
```bash
export PICO_DIR=`findmnt -S LABEL=RPI-RP2 -o TARGET -fn`
cp ./slab.uf2 $PICO_DIR
```
### upload-dbg
Directory: ./build
Requires: build-dbg
Builds and uploads debug firmware to the RP2040.
```bash
export PICO_DIR=`findmnt -S LABEL=RPI-RP2 -o TARGET -fn`
cp ./slab.uf2 $PICO_DIR
```
### build
Directory: ./build
```bash
cmake -DCMAKE_BUILD_TYPE=Release ..
cmake --build . -j $(nproc)
```
### build-dbg
Directory: ./build
Builds the keyboard firmware with development outputs.
```bash
cmake -DCMAKE_BUILD_TYPE=Debug ..
cmake --build . -j $(nproc)
cp compile_commands.json ../ # Copies the autocomplete information for ccls.
```
### clean
Deletes the contents of the build directory.
```bash
rm -rf ./build
mkdir build
```
### fetch-submodules
Fetches submodules if not already present.
```bash
git submodule update --init --recursive
```
## Technical Details
### Communication between devices
Devices communicate using I²C, but not in the typical way of all devices sharing the same bus.
For each device, I²C bus 1 is set to act as a master that controlls all on-board slaves (OLED screens, etc.), and can control another connected keyboard slave.
I²C bus 2 is set to act as a slave, controlled by the bus 1 (master) of another board.
Boards are chained together, with each board's I²C bus 1 connected to the next board's I²C bus 2, in sequence.
#### Packets
Packets are made of 1 `packet_type` byte, followed by the appropriate amount of bytes for that `packet_type`.
##### Packet types:
- `COM_TYPE_ALIVE` is 0 bytes, and is sent continuously to allow boards to know if the board that is controlling them is still alive.
- `COM_TYPE_ACCUMULATION_PACKET` is 11 bytes, and contains all the SQUIRREL data, to be accumulated as it travels through the keyboard from right to left.
- `COM_TYPE_WANT_ACCUMULATION_STATUS` is 0 bytes and is sent continuously until `COM_TYPE_DONE_ACCUMULATING` is recieved as a response.
- `COM_TYPE_NOT_DONE_ACCUMULATING` is 11 bytes, all ignored.
- `COM_TYPE_DONE_ACCUMULATING` is 11 bytes, containing the SQUIRREL data, as accumulated, from the leftmost board.
#### Sequence Diagram
```mermaid
sequenceDiagram
participant Board 1 (L)
participant Board 2
participant Board 3
participant Board 4
participant Board 5 (R)
# First communication.
activate Board 1 (L)
Board 5 (R) ->> Board 4: COM_TYPE_ACCUMULATION_PACKET
Board 4 ->> Board 3: COM_TYPE_ACCUMULATION_PACKET
Board 3 ->> Board 2: COM_TYPE_ACCUMULATION_PACKET
Board 2 ->> Board 1 (L): COM_TYPE_ACCUMULATION_PACKET
Board 5 (R) ->> Board 4: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 4 ->> Board 5 (R): COM_TYPE_NOT_DONE_ACCUMULATING
Board 4 ->> Board 3: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 3 ->> Board 4: COM_TYPE_NOT_DONE_ACCUMULATING
Board 3 ->> Board 2: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 2 ->> Board 3: COM_TYPE_NOT_DONE_ACCUMULATING
Board 2 ->> Board 1 (L): COM_TYPE_WANT_ACCUMULATION_STATUS
Board 1 (L) ->> Board 2: COM_TYPE_DONE_ACCUMULATING
activate Board 2
Board 3 ->> Board 2: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 2 ->> Board 3: COM_TYPE_DONE_ACCUMULATING
activate Board 3
Board 4 ->> Board 3: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 3 ->> Board 4: COM_TYPE_DONE_ACCUMULATING
activate Board 4
Board 5 (R) ->> Board 4: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 4 ->> Board 5 (R): COM_TYPE_DONE_ACCUMULATING
activate Board 5 (R)
# Second communication.
deactivate Board 5 (R)
Board 5 (R) ->> Board 4: COM_TYPE_ACCUMULATION_PACKET
deactivate Board 4
Board 4 ->> Board 3: COM_TYPE_ACCUMULATION_PACKET
deactivate Board 3
Board 3 ->> Board 2: COM_TYPE_ACCUMULATION_PACKET
deactivate Board 2
Board 2 ->> Board 1 (L): COM_TYPE_ACCUMULATION_PACKET
Board 5 (R) ->> Board 4: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 4 ->> Board 5 (R): COM_TYPE_NOT_DONE_ACCUMULATING
Board 4 ->> Board 3: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 3 ->> Board 4: COM_TYPE_NOT_DONE_ACCUMULATING
Board 3 ->> Board 2: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 2 ->> Board 3: COM_TYPE_NOT_DONE_ACCUMULATING
Board 2 ->> Board 1 (L): COM_TYPE_WANT_ACCUMULATION_STATUS
Board 1 (L) ->> Board 2: COM_TYPE_DONE_ACCUMULATING
activate Board 2
Board 3 ->> Board 2: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 2 ->> Board 3: COM_TYPE_DONE_ACCUMULATING
activate Board 3
Board 4 ->> Board 3: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 3 ->> Board 4: COM_TYPE_DONE_ACCUMULATING
activate Board 4
Board 5 (R) ->> Board 4: COM_TYPE_WANT_ACCUMULATION_STATUS
Board 4 ->> Board 5 (R): COM_TYPE_DONE_ACCUMULATING
activate Board 5 (R)
deactivate Board 2
deactivate Board 3
deactivate Board 4
deactivate Board 5 (R)
deactivate Board 1 (L)
```