From: Marko Mäkelä (Marko.Makela_at_HUT.FI)
Date: 2002-08-22 08:47:25
Niklas Ramsberg <email@example.com> wrote: > the text says something about the GAME and EXROM pins on the > expansion port (read: internal or external function ROM) being used > as output lines True, they can be used as outputs, just like the 40/80 column key line can be used. In my C128, I've misused the 40/80 line for selecting the C64 mode KERNAL. When the line is low, I get the original -03 version. When it is high, the C64 mode starts up with a different KERNAL. I can select the stock ROM either by pressing the 40/80 key down or by using a simple program (actually the cbmlink boot sector) that switches the computer to C64 mode with the 40/80 line set '0'. The document kernal-switch.html at http://www.funet.fi/pub/cbm/documents/projects/memory/ describes yet another modification: misusing the -GAME line for selecting the C128 mode KERNAL. The document also tells which KERNAL and Z80 BIOS locations you need to modify in order to disable the "go 64 when -GAME or -EXROM is low" misfeature. Marko Message was sent through the cbm-hackers mailing list
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