An actual running computer with actual RAM and ROM! Memory decoding logic was painful. I added a quad 74HC00 NAND gate along with the 3 to 8 decoder. Code in ROM copies lots of NOPs into RAM beginning at $1000 and then JMPs in. It’s merrily NOPing along through RAM. Memory mapped as 32K RAM $0000 to $8000, 8K ROM at the other end $E000 to $FFFF which leaves a 20K hole for future I/O or whatever. Need to add proper clock next.
More homebrew 6502
Part 1 : 8-bit Nostalgia and powering up the 6502
Part 2 : It lives! Adding a temporary clock and the free run
Part 3 : Memory map, address decoding and adding a ROM
Part 4 : Building an EEPROM programmer
Part 5 : More address decoding, adding RAM
More to follow
2 thoughts on “Homebrew 6502 : It runs”
Awesome and neat work so far, hope you have fun and good lick getting it working further!