Reading obsolete ICs... Mostek 3851 PSU

John Robertson wrote: I've read them in the past. Must have been around 1992 or so. I used a single-board computer based on the R6511Q microcontroller (6502-based), and wired the 3851 bus to GPIO port pins. There was simple firmware in 6502 assembly language, and it output the contents in S-record format out a serial port. The firmware generated all of the control signals for the 3851, including the clock, by bit-banging. IIRC, there was a minimum clock frequency spec for the 3851, but I didn't have any trouble meeting it. I did NOT try to ensure that all clock cycles were the same duration, which would have required cycle-counting various code paths, but the 3851 didn't care. Alas, I don't have the code any more, but that probably doesn't matter much since it's unlikely that one could find a 6511Q board. Regrettably I don't have time to develop another 3851 reader, but I don't recall there having been anything fundamentally difficult about it. Reading the 3870 single-chip micro is considerably more tricky.