al1f+@andrew.cmu.edu (Andy A. Lee) (05/07/88)
Christopher, Regarding your Centipede experiment, I can give you some assistance. First of all, there's a way to get around the RAM-vs-ROM protection schema: you built yourself a 'blank cartridge'; a cartridge that grounds the 'read-only' pin of the cartridge port. You see, when the 'read-only' pin is ground, the Atari won't write to its RAM where the cartridge resides ($A000-$BFFF) even though it is RAM. If you don't know where the 'read-only' pins are, let me know. I will look them up for you. There are two 'read-only' pins in the left cartridge port. One is for $A000-BFFF, and another for $8000-$9FFF. About 16K Cartridges, they come in different sizes and shapes. For example, one of the well known 16K cartridges, "Action!", has a 4K block of codes reside in the Atari at all time while 3 other 4K blocks of codes are being switched on one at a time. They also called 'bank selecting' cartridge. Although they claim to be 'un-copyable', I have seen some hackers managed it by modifing a 256K 800XL to simulate the bank switching. Although I don't do any Atari anymore, I still remember a lot from the old days. If you have any more questions, please don't hesitate to ask. * Andy *