jum Posted November 26, 2020 Share Posted November 26, 2020 I've recently been modding a "Pixels Past" 32k 5200 cartridge PCB to be able to switch between 2 16k rom images in the 32k EPROM, using an external switch. This setup assumes that the 16k rom is mapped to 0x8000 in the 5200 memory space. However I noticed that many 16k roms seem to be mapped to 0x6000, and then the last 8k of the rom is repeated at 0xA000. (I also noticed this when writing the Jum52 5200 emulator) What I'm curious about is why this was done? Was it maybe some kind of anti-piracy mechanism, to make it harder to copy the cartridge? Quote Link to comment Share on other sites More sharing options...
ClausB Posted November 26, 2020 Share Posted November 26, 2020 On the cart PCB are two 16K select lines: 4000-7FFF and 8000-BFFF. Each line goes to one ROM chip. Since 2 8K chips were cheaper than 1 16K chip, they split up the game addresses between the two ranges. Quote Link to comment Share on other sites More sharing options...
Giles N Posted March 17, 2021 Share Posted March 17, 2021 Is this of relevance to converting Atari 8-bit computer games to the 5200 console? Quote Link to comment Share on other sites More sharing options...
Shawn Posted March 19, 2021 Share Posted March 19, 2021 On 3/16/2021 at 9:24 PM, Giles N said: Is this of relevance to converting Atari 8-bit computer games to the 5200 console? Absolutely not. Quote Link to comment Share on other sites More sharing options...
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