Firmware for the lard61 keyboard.
Directories blink and usb_output contain boilerplate projects I used to test my PCB initially.
The main keyboard firmware is located under usb_device.
The usb_device project is currently a complete USB HID keyboard firmware for
the lard61.
I've also integrated a CDC USB interface with a tiny custom shell, to allow me to remotely interact with the keyboard and e.g. go into BOOTSEL mode by sending "flash" through a serial terminal.
When I designed the PCB, I naively omitted connections to the RP2040's debug pins (SWD, SWCLK). This means I can't remotely flash firmware during development and try stuff out quickly. To reprogram the firmware before the CDC USB interface was added, I had to physically short the BOOTSEL pins on the PCB.