On Mon, Apr 08, 2013 at 04:31:02PM +0200, Gerrit Heitsch wrote: > Even with RESET asserted, the VIC still displays a picture on the > screen. It can only do that if it is activly reading from RAM (and > ROM) to fetch the data to be displayed. > > If you want to be sure, you can tristate the CPU from the expansion > port using the _DMA signal. Isn't that similar to the scheme how CP/M cartridge works? The situation is somewhat familiar: an external device (a Z80 CPU in our case) wants to control the C64 bus, so it needs to disable the 6510. However it's interesting to note that CP/M cartridges have problem (?) with certain C64 models, otherwise maybe it's worth to learn from the schematics of the CP/M cartridge to control the bus externally maybe? Message was sent through the cbm-hackers mailing listReceived on 2013-04-11 07:00:04
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