nesdev.org

Does anyone know of a guide for how to burn an eprom to use on something like a repropak(http://www.retrousb.com/product_info.ph ... ucts_id=42)

Would someone also explain to me what is MMC1/3 etc and why their board is different and requires more chips?

I've been working with electronics for year but have recently become interested in NES development and reproduction so this is all a bit confusing.

Also would something like http://cgi.ebay.ca/G540-USB-Universal-E ... 4aa00162ee work for programming the NES eproms?
If not could someone recommend another cheap alternative?

Aituon wrote:Does anyone know of a guide for how to burn an eprom to use on something like a repropak(http://www.retrousb.com/product_info.ph ... ucts_id=42)

I don't think there is a guide, specially considering how simple the process is. You just have to split ROM files in 3 parts: header, program (PRG-ROM), tiles (CHR-ROM). Not all games have that last chunk (CHR-ROM), because they use CHR -RAM.

There are some tools that can help you split the files (I'll let others name them, because I don't use them), but you can do it even with an hex editor. The header is always the first 16 bytes of the file, and certain bytes of it will tell how big the next two parts (PRG and CHR) are.

Then you just use the EPROM programmer's software to burn the PRG and CHR to 2 chips.

Would someone also explain to me what is MMC1/3 etc and why their board is different and requires more chips?

These are mappers that expand the basic capabilities of the NES. The simpler ones simply allow the games to be larger than 32KB (the limit imposed by the system), but the most complex ones are able to expand even graphics and sound capabilities. Technically, like someone said recently, you could even put a PlayStation 3 inside a (big!) NES cart and use it as a mapper, as long as the graphics were sent to the NES in the form of 4-color tiles.

Anyway, several different mappers were used in commercial games, and if you plan on making carts for those games you have to take that into consideration, because very few mappers are interchangeable, so you gotta know what game uses which mapper/board. Bootgod's site is also a very good place to look mappers/boards up.

Also would something like http://cgi.ebay.ca/G540-USB-Universal-E ... 4aa00162ee work for programming the NES eproms?

It probably will. The page says it works with 4000+ devices, and the chips used on the NES are very common standard ones, and it would be crazy if those weren't part of the 4000.

That EPROM programmer looks like it could work, but I'd really suggest you ask the seller for a few things, to make sure it's not a scam and it's what you want. Ask for a full-resolution picture of the device to be emailed to you, and ask for a list of the devices the programmer supports. Also, remember that to erase an EPROM you will need a strong UV light. There are cheap Chinese made UV EPROM erasers on eBay which should do that easily, which is where I got mine.

As for the rest, read the following:
http://nesdev.com/NES%20EPROM%20Conversions.txt
http://www.raphnet.net/electronique/nes ... art_en.php
http://www.romhacking.net/utils/683/

Ignore the first one if you're using one of Bunnyboy's repropak boards, since his instructions will walk you through installing the chips.

I'm also trying to make a dev cart, or actually a joystick test cart, got the programmer, eproms, joystick.nes file, a SMB cart socketed and cut out for eprom installation and removal ease, and UV eraser if needed.
Now i'm stuck on splitting the rom, i'm using "rom splitter 1.0" from shawn crawford, it says the rom has 16k prg and 8k chr SO I assume I need to program two eproms, however the auto split errors out before I can get that far. "The rom did not split correctly (incorrect CHR Bytes?)"
It gives the same error is I use the manual split mode.
I loaded a SMB1 rom and the program gives the same error, wont split correctly??? WTF?
Of the dozen or so ROMs i've tried only castlevania 2 didn't error out...
My other concern, my EPROMS are 12.5V, will that matter? Also the cheap chinese programmer I bought says its only for ? to 6.5V... Am I screwed there too? It listed the chips I bought as compatible with the programmer...

UVEPROMs typically use a higher voltage for writing than for reading, and they have a Vpp pin just for this voltage. Many programmers have a separate power supply to take this voltage.

tepples wrote:UVEPROMs typically use a higher voltage for writing than for reading, and they have a Vpp pin just for this voltage. Many programmers have a separate power supply to take this voltage.

So if they wont burn correctly then I need to feed the EPROM 12.5V seperately?

You shouldn't have to, all EPROM programmers will support the VPP voltage. Every EPROM needs it (AFAIK).

The reference to 6.5V is probably the VCC voltage. There actually are some 5V EPROMs that require VCC to be something higher than 5V during programming. So if you burn (for example) an M27C512, check it in the parts lists before selecting generic 27C512.

akaviolence wrote: Now i'm stuck on splitting the rom, i'm using "rom splitter 1.0" from shawn crawford, it says the rom has 16k prg and 8k chr SO I assume I need to program two eproms, however the auto split errors out before I can get that far. "The rom did not split correctly (incorrect CHR Bytes?)"
It gives the same error is I use the manual split mode.
I loaded a SMB1 rom and the program gives the same error, wont split correctly??? WTF?
Of the dozen or so ROMs i've tried only castlevania 2 didn't error out...

Well, I still need to solve this issue before i can even try to burn, anyone got any ideas?

akaviolence wrote:

akaviolence wrote: Now i'm stuck on splitting the rom, i'm using "rom splitter 1.0" from shawn crawford, it says the rom has 16k prg and 8k chr SO I assume I need to program two eproms, however the auto split errors out before I can get that far. "The rom did not split correctly (incorrect CHR Bytes?)"
It gives the same error is I use the manual split mode.
I loaded a SMB1 rom and the program gives the same error, wont split correctly??? WTF?
Of the dozen or so ROMs i've tried only castlevania 2 didn't error out...

Well, I still need to solve this issue before i can even try to burn, anyone got any ideas?

I am not very sure but perhaps the ROM file(i.e. .nes one) you are using is a hacked/amended one.

akaviolence wrote:

akaviolence wrote: Now i'm stuck on splitting the rom, i'm using "rom splitter 1.0" from shawn crawford, it says the rom has 16k prg and 8k chr SO I assume I need to program two eproms, however the auto split errors out before I can get that far. "The rom did not split correctly (incorrect CHR Bytes?)"
It gives the same error is I use the manual split mode.
I loaded a SMB1 rom and the program gives the same error, wont split correctly??? WTF?
Of the dozen or so ROMs i've tried only castlevania 2 didn't error out...

Well, I still need to solve this issue before i can even try to burn, anyone got any ideas?

I wrote a custom DOS program to split iNES into prg and chr. Let me know if you want that.

@ Nadia - Yeah i'll try your prog, maybe it will work for me...
At this point i'll try anything.
I've tried ROMs downloaded from two different sources, though I still don't know how to verify their integrity.
I can't imagine the joystick.nes ROM would get any attention as far as hacking/amending???
I did "play" the joystick.nes ROM with an emulator and it worked great, exactly what I need to test all the controllers I buy and sell, I play SMB for a while to try to test all the controller buttons and its such a time consumer...
BTW is there a different test ROM that tests the zapper?

BTW is there a different test ROM that tests the zapper?

I haven't used one so far. Please note that zapper doesn't work on LCD/TFT screen.

Nadia wrote:Please note that zapper doesn't work on LCD/TFT screen.

Except in one trivial case. This is a test ROM for the trigger only, not the photosensor.

@ Nadia - Got your prog to work, renamed the .prg and .chr files to .bin and neither would burn. Keep getting;
Start go...
Write...Error at:00000:(FF)

Maybe my cheap chinese programmer isn't up to the task? Its a USB top853.

akaviolence wrote:@ Nadia - Got your prog to work, renamed the .prg and .chr files to .bin and neither would burn. Keep getting;
Start go...
Write...Error at:00000:(FF)

Maybe my cheap chinese programmer isn't up to the task? Its a USB top853.

have you been able to burn any ROM successfully so far?

I mean it does not look like a problem with the files but as you said perhaps the eprom programmer you are using works in a different manner.