Posted By
siz
on 2012-01-25
04:51:47
|  Re: First Beta Release of Diag264 (0.2B)
You made me uncertain: I thought that only plus/4 contains a PIO at $fd10. I've to check the schematics. Or better: the pictures I took last time when I've disassembled my C116.
Well, I have a nice shot of the C116 mainboard: it has only one PIO for the keyboard selection. I've checked the schematics in the Zimmers archive and found (though crock's recent thread on CBM Hackers list helped a bit) that on the C116 there is a 74LS125 that gates the casette sense for the $fd10 chip select but it's connected to D2 only so all the other data lines are floating in those machines. I'll extract my detect routine from the monitor source (as it's burned in an EPROM and that is in my plus/4 rather than on a cartridge) and will try it on the C116 today.
Edit: I made the expansion area scanner and ran it on a C116 and a plus/4. The + symbol means that a stable result is read for at least 255 reads and - means (of course) the opposite).
Edit2: I've uploaded the scanner here in case someone wants to try it out.
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