I've started reverse-engineering some code from a #Mostek #MK3870 (Fairchild #F8 instruction set). Only 1408 bytes of code, which is roughly a thousand instruction, and 640 bytes of table. It uses interrupts from a timer and a photo interrupter. There's a state variable with about 8 values that controls what the interrupt handler does. Aside from a data buffer, and a pointer into a ROM table, there appear to be about ten variables. I've figured out two of those so far.
#reverseengineering

A 1970s Mask ROM Microcontroller Spills Its Secrets https://hackaday.com/2023/09/30/a-1970s-mask-rom-microcontroller-spills-its-secrets/ #ReverseEngineering #Microcontrollers #firmwaredumping #maskrom #ROMdump #MK3870 #Mostek #3870