a2stuff / prodos-drivers

Apple II ProDOS-8 system files that run on startup and install clock drivers, ramdisks, and other utilities
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NSC driver activates Z80 card, hangs #15

Closed inexorabletash closed 1 year ago

inexorabletash commented 1 year ago

The NSC driver installer starts off by checking each slot, bit-banging into the card's memory space to try and detect an NSC installed.

If a Z80 card is encountered before the NSC is hit, the Z80 card is activated, causing the 6502 to halt.

This doesn't occur on Virtual II if you have an NSC, because the NSC appears in the Slot 3 ROM space, which is the first slot checked. But it repros in Virtual II if you configure a machine with a Z80 card and without an NSC or Thunderclock.