Using the Arduino to test boards
Because of the complex logic I had to use an Arduino to check these everything.
Here is Weird CPU mark I, using the Arduino as a PROM and testing the PC board (the stack consist of the IO board, the timing and memory board (only the RAM is installed) and the PC board). The access time of the Arduino PROM was about 1.3 us so I slowed down the CPU clock from 1 MHz to 100 kHz:
Here is the stack disassembled:
You may note the repeated use of read and write decoder chips (2) on each board (generally the first two on the left). 41 tracks is not enough to decode all the hardware addresses just once.
Here are the build notes for one of the boards:
Without the Arduino I doubt that I could have completed the project.