The ALU is too complex for me to fit on one PCB, so i've broken it into 5 seprate PCBs which will stack. I finished the first board and made some breakout boards to make testing go faster for this project. One just converts between a 2x5 header (which I'm using to route the main bus and power throughout the computer) to a section of female header pins. The other lets me read high/low values of 8 pins or write high/low values to 8 pins.

(The blue tape is just covering the strip of 8 LEDs because they are too bright)

Here is ALU Board 1:

This board houses the ALU's three registers. I forgot to allow the registers to be clocked individually, so I had to cut the clock trace and add some bodge wires.

I've got ALU boards 2-5 designed and ordered, along with the RAM module and 2 other boards for the CPU (they house the program counter, instruction register, and a bank of flipflops that lets the user specify at boot-up which flash memory device to load the program from), so those will be coming along shortly.