Posted By
crock
on 2021-03-29
16:42:42
 |  Re: 264 Magic Cartridge, new banking cartridge
I do not think it is possible without power cycling the machine. The reason is simple, the buffered /reset signal that is triggered by the button and exposed on the cartridge port only resets the CPU and the ROM bank latches, and not TED. TED has no /reset pin.
This is a problem because the TED implements the virtual registers at $FF3E and $FF3F which select ROM or RAM when reading from the upper 32k of address space. If reset is triggered when RAM is enabled, the CPU resets and starts executing from whatever address is read from the reset vector at $FFFC in RAM which could be an uninitialised random address causing the machine to hang, or a vector to some message or to restart the game.
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