Factor of Matt

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2024-09-21 17:30:03

The DesTestMAX project aims to improve upon Commodore’s Dead Test cartridge by using a more comprehensive memory test strategy and provide easier to interpret diagnostic output.

DesTestMAX utilizes the MAX (or ULTIMAX) cartridge mode as it allows us to place code directly in the $E000-$FFFF block of memory that gets executed as soon as the system resets. Such a situation allows the DesTestMAX code to take complete control of the system right from the get-go. Unlike the regular Commodore 64 boot process, DesTestMAX makes very few assumptions about the state of the machine and can produce usable results even with a severely broken machine.

The 6510 CPU, VIC-II and PLA need to be functional, though the ROMs, CIAs and SID are not required and can be removed if socketed.

The big drawback to MAX mode is that only the first 4K of system memory is available to the CPU. DesTestMAX then can’t be a fully-comprehensive memory test, but it can be a great help when faced with a Commodore 64 that shows nothing but a black screen.