Hey guys, I have sucessfully completed building a development cartridge for the NES! It runs mapper 0 games, but I currently don't have a game on it- I have an NES deck testing program on there. Pics and instructions will be coming as soon a ssomeone shows some interest. BTW, this was remarkably easy to build, I bet anyone could do it. I need to upload some pics before I can tell you guys any more... just say what you think while you wait.
edit: here are pics
As for the wiring, it is fairly simple, you just socket the chip directly, if you use the 27c256, that is. The you just wire a simple switch for the H or V mirroring. I don't have a pic of the front of the PCB yet, mebbe in a bit.
Last edited by arfink on Sat May 13, 2006 8:05 pm, edited 5 times in total.
arfink wrote:Hey guys, I have sucessfully completed building a development cartridge for the NES! It runs mapper 0 games, but I currently don't have a game on it- I have an NES deck testing program on there. Pics and instructions will be coming as soon a ssomeone shows some interest. BTW, this was remarkably easy to build, I bet anyone could do it. I need to upload some pics before I can tell you guys any more... just say what you think while you wait.
ok, heres the deal. I can't seem to get my picture upload to work, for some reason. Maybe later tonight, or something. Anyway, this thing uses two 27C256 eproms, one for the PRG and one for the CHR. I removed the CHR and PRG chips from a gyromite cart. and put in two 28 pin sockets. I also had to cut a hole for the chips, so you don't have to take the whole cart apart when you want to reprogram it. I also have a handy little switch to change from horizontal to vertical mirroring. The only problem with this cart is that it only runs mapper 0, and that it uses eproms. You need a UV light to erase them, which I don't have. My dad takes them to his office where he has a special UV eraser for them. I am thinking of upgrading to the 29C256 so they are Flash, that would be better. Pics coming soon, I hope...
What did you use? Standard EEPROMs or FlashROMs? Also, did you make any custom programmer for it if the later? Shouldn't be too hard to wire up a nes port to a || or IO port to program.
I am using eproms right now. I want to use some flash chips, but I need to buy them first (no money, lol) I am just removing the chips from the sockets and burning them with a regular eprom burner. Once I fugure out the flash I want to try making something that other people could program without using a special chip programer. I would use some Static RAM chips for the CHR and PRG, that would be fast, cheap, and easy to write to with the PC. But I had to start with something easier. Also, horizontal and vertical mirroring refers to how the graphics are layed out in memory. Some programmers want to have the tiles arranged like this:
0 4 8
1 5 9
2 6 10
3 7 ...
While other like it like this
1 2 3 4
5 6 7 8
9 10 ....
It is just that some games do it one way and some do it another way.
Also, I have been investigating the use of some battery backed Static Ram instead of EPROMS, and making a custom programmer. Would anyone be interested in such a thing? If I can work up a good design I might sell some.
Well, actually, the programming device I referred to would not be able to program eproms without modification. The intent was to have a special cartridge with battery backed static ram instead of ROM chips, which could be programmed by a special device hooked up to the computer. The reason I would use static ram is it can be erased by just disconnecting the power from it, and it is easy to program and you don't need an odd volage like 12.5 volts in order to program the device. I have been working on some scematics and intend to build a prototype as soon as I have the money to buy some parts I need. When its done I'll post it in a new thread.
