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RC6502 Apple 1 SBC unresponsiveness

Open denjhang opened this issue 3 years ago • 7 comments

截图未命名0113225257

denjhang avatar Jan 13 '22 15:01 denjhang

Pressing the reset key on the sbc will bring up a "/", nothing happens to keyboard input, it seems to freeze.

denjhang avatar Jan 13 '22 15:01 denjhang

Press the reset button on the arduino nano, "RC6502 Apple 1 Replica" will appear

denjhang avatar Jan 13 '22 15:01 denjhang

The RC6502 Apple 1 Replica message is from the Nano, and that just indicates that the Nano is talking to the PC and thinks it's talking to the SBC. Resetting that is entirely independent of resetting the SBC.

The \ prompt is from the SBC; that's how WozMon says that you can start typing input. So if you're seeing that, you know that the Nano is reading the "screen" output from the SBC. If typing doesn't echo the characters you've typed (or a new prompt if you hit Return or Esc), it could be that your typing is not getting to the Nano, but more likely there's a problem with the connection between the Nano and the SBC's keyboard circuitry.

0cjs avatar Jan 18 '22 01:01 0cjs

I've replaced a few sets of chips and the situation is still the same, it doesn't seem to be a chip problem. Can anyone tell me what to do?

denjhang avatar Jan 19 '22 10:01 denjhang

I guess the next step might be to put a 'scope or logic probe on the "keyboard" outputs from the Nano to the PIA and make sure it's toggling those lines when you type at the console?

0cjs avatar Jan 20 '22 00:01 0cjs

At the moment I found out that the cause is a bug caused by corrupted SRAM.

denjhang avatar Jan 30 '22 17:01 denjhang

I had exact the same Problem. Used HM65256 instead of HM62256 Chip. This was my mistake. Thank you for pointing this out, @denjhang

explit7 avatar Nov 23 '23 19:11 explit7