Theory of Operation?

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Don't Panic. Please wash hands.
  • Can someone explain a little bit of the theory of operation for the Chameleon? Things like the process the cartridge goes through during boot-up. How does it disable the 6510 inside the C64? Does it use the C64's internal RAM? If it does not, how is it isolated from the memory in the FPGA?

  • The 6510 is disabled by pulling low on DMA. It also puts the machine in Ultimax mode by pulling low on the GAME line. This results in disabling most of the internal memory of the C64 and prevents I/O to be mapped out, so it is guaranteed to be available. There is an additional small trick we do to feed the VIC-II with data from the Chameleon. The memory in the C64 isn't used at all, except for the color ram. The contents of kernal and basic ROM can be copied, but are not used during normal operation.


    The programmers manual of the Chameleon gives details about the boot rom, startup and the menu system memory layout if you want to know more about that subject.

  • The last reply was more than 365 days ago, this thread is most likely obsolete. It is recommended to create a new thread instead.