------------------------------------ | "Vorwaerts, wir muessen zurueck !" | ------------------------------------
Back in 2002, the 6502 disappeared out of all cataloges.
[Edit: The 6502 showed up at Mouser/Germany in 2012 again.]
Wanted to know, if it's possible to build a binary compatible CPU
with the things I had in the drawer:
74LS parts, 27C512 EPROMs and a fast static RAM from an
old 80386 motherboard.
Now here the results.
Note, that the Bus timing is different from the 6502.
The CPU:
| File | Description |
| cpu.txt | short description of the CPU |
| system.jpg | big picture of the Computer |
| cpu.jpg | CPU from the side |
| cpu_1.jpg | CPU, PCB 1 |
| cpu_2.jpg | CPU, PCB 2 |
| m02_3.zip | Eagle3.55 schematics, layouts, SourceCode. |
Schematics in JPG format:
Other pictures:
| Datei // File | Beschreibung // Description |
| crt.jpg | CRT von der Seite // CRT from the side |
| crt_1.jpg | CRT, Platine 1 // CRT, PCB 1 |
| crt_2.jpg | CRT, Platine 2 // CRT, PCB 2 |
| mem.jpg | Speicher // Memory |
| irq.jpg | Tastatur, IRQ, Reset // Keyboard interface, IRQ, Reset. |
Oops, It's 2008 already ?
I'm attaching a ZIP file with the rest of the layouts/schematics
for this project. They are partially untested, and there will be
no support. You have been warned.
So if you build them and they won't work, don't blame me.
From here on, you're on your own. Good luck and god speed...
[2016: Edit: ] [ ] [ Might be possible to give M02 a more 6502 compatible bus timing. ] [ This requires sampling A15..0 with 74573 transparent latches, ] [ and using a different microcode. ] [ ] [ Downside is, that the ALU would have to run 4 times faster ] [ than the bus (4 MHz for a 1 MHz 6502 that is), ] [ but the M02 ALU wasn't able to go faster than 3 MHz. ] [ ] [...and that's what had triggered my interest in ALU design. ] [2016: Edit: some of the 65816 instructions probably have bugs... ]
More technical info can be found in the "articles" section:
(c) Dieter Mueller 2002,2003,2004
