Heaven/TQA Posted January 15, 2006 Share Posted January 15, 2006 would that be possible? the dificulty is that i need the RAM in the area $1000-$cfff so i can not pleace ROM there but would it be possible to have a cart $f000? or $0500ff? never played around with carts that's why i am asking... Quote Link to comment Share on other sites More sharing options...
Rybags Posted January 15, 2006 Share Posted January 15, 2006 Can't be done. Cartridges only have enough address lines to allow 16K of addresses. Aside from that, bank selecting would be the only option. And even then, as a minimum you have to use $B000-BFFF for ROM. I imagine their might be some way to have RAM there, but don't know if a method exists. Early bank select schemes used the address range $D500-D5FF, and output a signal on a line called CARTCTL (I think) which bank-select hardware can use to employ bank-switching on the cartridge. I've heard of systems which allow a small ROM at $5000, but don't know if they existed on production 800s. Quote Link to comment Share on other sites More sharing options...
classics Posted January 15, 2006 Share Posted January 15, 2006 Use a switchable cartridge so you can turn off the ROM and use all of ram after loading. If you send me your program I can see if it will work on 1mbit flash cartridges. Steve Quote Link to comment Share on other sites More sharing options...
+warerat Posted January 21, 2006 Share Posted January 21, 2006 Can't be done. Cartridges only have enough address lines to allow 16K of addresses. Aside from that, bank selecting would be the only option. And even then, as a minimum you have to use $B000-BFFF for ROM. I imagine their might be some way to have RAM there, but don't know if a method exists. Early bank select schemes used the address range $D500-D5FF, and output a signal on a line called CARTCTL (I think) which bank-select hardware can use to employ bank-switching on the cartridge. I've heard of systems which allow a small ROM at $5000, but don't know if they existed on production 800s. 1000686[/snapback] You can disable the ROM by dropping RD4 and RD5 on the cart slot. Grounding RD4 would show the ram from $8000-$9FFF and RD5 would be $A000-$BFFF. Some bank switched cartridges latch them through /CCTL so you can turn off the ROM. The XL/XE has the self-test ROM from $5000-$57FF selectable via PB7. Quote Link to comment Share on other sites More sharing options...
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