See images on the right! The 'rev 1 prototyoes' of these two boards finally showed up after an excruciating _two weeks_ door to door (even grown ups become impatient children sometimes!) and look very fine! The two remaining boards to lay out are the base pcb (RAM, ROM cartridge slot, joystick ports, keyboard/IO chip, and audio chip, and all the headers and interconnects) and cpu adaptoer pcb (so can hook up a Z80, 6502, 6809, 68000, whatever) to the base board. The cpu board should be pretty easy .. and similar to half the GPU board in fact. Just the cpu IC, any ISP header, LED and debug headers needed, its required caps and oscilators, ring of headers around it for break-out-board sake, and the 'zikzak standard cpu header' (to be defined soon). For something like an atmega644 it should be a pretty straight forward board, so that'll be my first one I think ..
FWIW, an atmega644 is a great little chip (that and the stm32f are my favorite chips this year) .. they can run without external RAM/ROM or nearly anything. Oscilator.. optional! Decoupling caps.. runs without 'em! Anyway, I'll be breadboarding down an atmega644, its 4 power lines and 2 decoupling caps, and then serial over to the GPU board, and voila, instant test platform. Well, secondary test platform .. the initial test platform is the GPU as a standalone machine. It wonks up the display when its doing anything really, but thats okay for a test.. should be trivial to JTAG over the ISP port to flash it and get some serial in/out going, and drive the VGA (code already done); maybe add some external buttons via the BoB header, for rotating through VGA demos, etc. Going to be a fun week!