Firmware for the Byte Arts MIDI Rocker LX (MIDI drum adapter for Rock Band and Guitar Hero). This firmware is for the PIC4550 microprocessor. The code was developed using MPLAB 8 from Microchip, which you can download from their website. New firmware can be loaded using the bootloader that is pre-programmed into the MIDI Rocker, or you can attach a PIC programmer to the IDC programmer header on the MIDI Rocker motherboard.
Schematics and PCB layouts are at https://github.com/ByteArts/MIDI-Rocker-LX_Hardware