ROM Reader

This is a board that I designed to allow me to read the memory from some masked ROM processors. I used this to pull the firmware from the 38880-57B40 TCM processor, it can be used with 40 and 42-pin processors and with adapters with any Motorola based processor that has a special test mode. The only unusual part about the design is IC7 and its associated logic, this allows the reset vector to be pulled from external memory but then switches the higher EPROM addresses out of the memory map which allows the internal reset vectors to be read. An FTDI USB module is used for the interface to the PC because this allows odd baud rates to be used. The PCB has provision for additional connectors fitted to allow it to be used as a single board computer (SBC). A 27C256 EPROM can be used for the programme memory or an emulator can be used if real time code modifications are necessary.