I've had almost all the equipment to make a cart at work as I am a computer tech at an electronic repair shop. All but the EPROMs. I just got my hands on a two AM27C256 EPROMs but I can't seem to figure out what pin/board modifications I need to make in order for these EPROMs to work.
When I compare the EPROM Pin outs hosted by NESdev to the pin outs on the AMD datasheet pin 27 does not match. On the NESdev chart it is address input 'A14' while the AMD datasheet shows it as the 'Program Enable Input'. Does this make this specific EPROM unusable for my pourposes?
If this EPROM is usable then I am also hitting a wall with the cartridge PCB conversion. The Dick Tracy donor cart has a 128Kbit PRG ROM. According to the NESdev ROM pinout chart the PRG ROM has Address Inputs from 0-16 while the AMD EPROM datasheet and NESdev EPROM chart show the 27C256 EPROM having only 15 Address Inputs (A0-A14). I keep reading about people using larger memory sized EPROMs, but having to fill the entire EPROM memory with the same code repeated. I must be not understanding something here as to me it looks like there are more Address Input lines in the 128Kbit Mask ROM than a 256Kbit EPROM.
When I compare the EPROM Pin outs hosted by NESdev to the pin outs on the AMD datasheet pin 27 does not match. On the NESdev chart it is address input 'A14' while the AMD datasheet shows it as the 'Program Enable Input'. Does this make this specific EPROM unusable for my pourposes?
If this EPROM is usable then I am also hitting a wall with the cartridge PCB conversion. The Dick Tracy donor cart has a 128Kbit PRG ROM. According to the NESdev ROM pinout chart the PRG ROM has Address Inputs from 0-16 while the AMD EPROM datasheet and NESdev EPROM chart show the 27C256 EPROM having only 15 Address Inputs (A0-A14). I keep reading about people using larger memory sized EPROMs, but having to fill the entire EPROM memory with the same code repeated. I must be not understanding something here as to me it looks like there are more Address Input lines in the 128Kbit Mask ROM than a 256Kbit EPROM.