This software is designed to interface a BB Q10 keyboard matrix as a I2C slave.

The key presses are put on a FIFO, which can be queried over I2C.

The software also allows for basic configuration of the behaviour.

The software also controls the backlight of the keyboard.

See Protocol for details.

See the targets directory for a list of available targets.

git clone https://github.com/arturo182/bbq10kbd_i2c_sw.git
cd bbq10kbd_i2c_sw
make TARGET=<target>

Here are libraries that allow interaction with the boards running this software:

• Arduino
• CircuitPython
• Rust (Embedded-HAL)

The device uses I2C slave interface to communicate, the address can be configured in app/config/conf_app.h, the default is 0x1F.

You can read the values of all the registers, the number of returned values depends on the register. It's also possible to write to the registers, to do that, apply the write mask 0x80 to the register ID (for example, the backlight registred 0x05 becomes 0x85.

Data written to this register is discarded. Reading this register returns 1 byte, the first nibble contains the major version and the second nibble contains the minor version of the firmware.

This register can be read and written to, it's 1 byte in size.

This register is a bit map of various settings that can be changed to customize the behaviour of the firmware.

Defaut value: CFG_OVERFLOW_INT | CFG_KEY_INT | CFG_USE_MODS

When an interrupt happens, the register can be read to check what caused the interrupt. It's 1 byte in size.

After reading the register, it has to manually be reset to 0x00.

This register contains information about the state of the fifo as well as modified keys. It is 1 byte in size.

Internally a PWM signal is generated to control the keyboard backlight, this register allows changing the brightness of the backlight. It is 1 byte in size, 0x00 being off and 0xFF being the brightest.

Default value: 0xFF.

Currently not implemented.

Default value: 10

Currently not implemented.

Default value: 5

Reading or writing to this register will cause a SW reset of the chip.

This register can be used to read the top of the key FIFO. It returns two bytes, a key state and a key code.

Possible key states:

v0.3:
- Change values sent for mods if CFG_REPORT_MODS is enabled so they don't overlap the buttons
- Send different value for left and right shifts if CFG_REPORT_MODS is enabled
- Change FIFO size to 31 so it's reported correctly in REG_KEY if FIFO is full

v0.2:
- Add support for KEY_LEFT2 and KEY_RIGHT2
- Add the Keyboard FeatherWing target

v0.1:
- Initial release