nesdev.org

Turns out the Parallel Port on the laptop I was using to connect the programmer to was not compatible enough. All the "issues" I was having were also non-issues. The low voltages were all "good enough" as the EPROM's datasheet showed that trigger voltages needed to be at a MINIMU...

I was considering one of those but I could not find any 42 pin dip adapters for programming larger EPROMs such as the 27c322 for the Sega Genesis or SNES. The other options left would have been the Willem or the GQ-4X, and the Willem was a third of the price with the needed adapter. I guess my fruga...

I recently bought a cheap Willem on eBay to play around with making some reproduction carts for myself and a friend but it seems the programmer is defective (or so I think) and it is too late to return it. The issue I am having is that if fails to write to EPROMs on the same location every time on t...

I'm doing some research into converting my Hunt for Red October cart into a Little Samson cart and using NesCartDB I find that HfRO uses a MMC3B mapper while LS is needs a MMC3C mapper, even though NesCartDB shows that both games use the same PCB Class, iNES Mapper, and PCB Name. Can I use HfRO as a...

Am27C256 is a 32Kx8 parallel UV EPROM. Its pinout matches the 32KBytes pinout seen the old doc and in the wiki page . Vpp needs to be be 12.75 V during writes. Might you have confused bits and bytes? Yes. Yes I have. It seems the NESdev ROM Pinouts are organized by KBytes, not KBit. I was comparing...

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...