Aaron Spinks Posted November 15, 2019 Share Posted November 15, 2019 I have this pictured homebrew player. Works great with 27c256 eprom but I want to use the W27C512 eeprom. Is it possible? Also will I be able to use this player for the super game roms? Yes I have the sgm. Quote Link to comment Share on other sites More sharing options...
Tursi Posted November 16, 2019 Share Posted November 16, 2019 You can not use this PCB for games larger than 32k, they require a different mapper chip. You could use a 27C512 EPROM but you can still only use 32k of it. From looking at the pinouts, it should just work. To be safe, double the ROM by burning the 32k image to both the first 32k and last 32k of the ROM, then it won't matter what the PCB holds pin 1 at. Quote Link to comment Share on other sites More sharing options...
Aaron Spinks Posted November 16, 2019 Author Share Posted November 16, 2019 Is there a pcb for larger games as I am getting my sgm next week. I have tried doubling my roms and it still doesn't work. Someone suggested start writing at line 8000h? Quote Link to comment Share on other sites More sharing options...
ChildOfCv Posted November 16, 2019 Share Posted November 16, 2019 First of all, if you program the chip, make sure you use the correct chip type. If it applies programming voltage to pin 1 of your W27C512, it will probably fry it. Also, it won't apply programming voltage to pin 22 like it's supposed to. With that out of the way, did you try reading the programming back to make sure you got what you wanted? Normal operation for a W27C256 has pin 1 at +5V, so your addresses will always be in the 0x8000 range on a W27C512. So yeah, write a bunch of zeroes to the first 32K if anything, and then write the game to the high 32K. Quote Link to comment Share on other sites More sharing options...
Aaron Spinks Posted November 16, 2019 Author Share Posted November 16, 2019 Writing my files stating at the 8000 line works perfectly! Quote Link to comment Share on other sites More sharing options...
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