After far too long, the next phase of pre-PCB testing is being initiated.
Here are three modules (from left, 64kB RAM, Z80 CPU and Arduino/AVR). Audio and Video are not yet rebuilt for this phase. RAM, CPU and Arduino/AVR are the critical components to get it running at all.
These boards are built from the schematics ( I hope :)), and any changes here will be implemented in KiCAD right away. So when this works, the PCB's based on it should be reasonably safe to order.
The Arduino/AVR bit has moved from an Arduino Nano to a plain ATmega32A. This gives me more pins, but more importantly, it's pin compatible with the ATmega1284P, which will most likely be the one used in the end.
This means it won't have an Arduino bootloader, but will be flashed via an USB-ASP (partly visible on the right side) directly. For maximum library compatibility, the actual code will still remain mostly Arduino-based though. An FTDI will be added to this setup as well for serial communication. So some code needs to be rewritten and adjusted for new pin configurations and such, but that shouldn't be too much of an issue.
The boards are connected via the 50pin ribbon cable in the back. This is just an old internal Narrow-SCSI cable I had in a drawer. I don't intend to run fast enough for the extra length to disrupt much at this point. The final PCB's will use the same way to connect, but that will be using a cable of more optimal length.
The setup got slightly less messy with the bus connecting the boards :) #Arduino #AVR #Z80