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Comment by qwertyuiop924 | Hacker News Reader

I want to learn 6502. Unfortunately, it's a right pain getting a 6502-based machine to run. The efficient instruction fetching means you have to be really careful about wiring and memory fetch speed. And I don't have any old 6502 systems on hand. All I've got is a Gameboy, and that's somewhere between the Z80 and the 8080. So I'll probably learn that at some point (although the GB is basically the Z80 with all the good bits stripped out).

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Not really. You can get up to about 1Mhz on a breadboard, and my wire-wrap SBC works at 4Mhz without any issues. If you did run into timing issues, you could just underclock the whole thing.

>Not really. You can get up to about 1Mhz on a breadboard, and my wire-wrap SBC works at 4Mhz without any issues.

That's true, but for a newbie like myself, it would be rather hard to get going.

Also, the current run of the W65C51 is majorly broken, which makes getting the project going even harder (most alternatives to the W65C51 are no longer sold).

I built my SBC without any prior experience. You pretty much just have to connect all the adress and data lines, and then figure out the chip selection logic. I used an MC68B50 for the UART, which can still be found very cheaply on eBay.

Huh. I guess it's worth a shot, then... I'll have to look into using a MAX232 for connecting it to my terminal, as well (I do, in fact, have a terminal: A Z19, in fact).

Might as well build a Z80 system while I'm at it. And Zilog's UARTs are quite nice, or so I've heard.

One thing I'd recommend is to try to find some 5V erasable EEPROMs, so you can reprogram it in-system wthout having to transfer it over to a dedicated (and expensive) programmer.

I went with a 12V-EEPROM at the time, so I had to write my own emulator to speed up my development cycles :)

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