Andre Fachat has written a post on his 6502.org blog detailing his DIY 6502 computer build. “I have built a DIY 6502 computer, which is mostly TTL logic only except for 65xx chips and ROMs, but the most TTL-ish part is the blitter: A block transfer engine that DMAs memory area from one location to another. It falls into the “over-complicated” category, it has 30+ 74xx TTL logic chips, with only one CPLD for the sequencer. It can copy from single (e.g. I/O) address to memory or back, can count addresses forwards and backwards, and can even use offsets.”

For more details, schematics, code and how it works for the blitter see Andre’s blog.