After watching on the sidelines for the last few, I’ve decided to enter RetroChallenge 2010. Since I enjoy hacking on FPGAs, I think I’ll transform an FPGA eval board into a COSMAC Elf. I developed a partial VHDL implementation of the CDP1802 processor architecture a while back, but only to the point that it could run CamelForth. I still need to test the instructions not used by CamelForth, “load mode” (necessary to enter programs from toggle switches on the Elf), and interrupts. I also need to develop a VHDL implementation of the CDP1861 “Pixie” graphics chip to run some of the demos and CHIP-8 games. I could either generate monochrome NTSC video, or maybe include a scan converter to drive a VGA monitor.
For the hardware, I’ll need to wire up the switches and LEDs, and possibly a small circuit to produce a composite NTSC signal from two CMOS outputs of the FPGA.
If time permits, I might also implement the RCA Studio II game console.