EPRom question, but possibly not the one you're used to...

AB_Positive · Post by **AB_Positive** » Tue Oct 21, 2008 8:24 am

Hello, long time lurker, just not getting into things. I figured I'd start by making repros of games I wanted (Mini Putt, Rockman Exile and Earthbound Zero to start) before delving into programming. However I've hit a snag.

I'm used to soldering and have all the burning tools needed and whatnot but a few questions that I can't find answers to but I'm sure are easy.

1) I have a pure-USB willem programmer - however do I still need an AC adapter to burn the flash/eproms properly or does the USB power do the job itself? Remember - pure usb not the parallel based ones.

If I need one, where is a good place to get it?

2) The soldering act itself is quite easy for me, I'm a veteran of region modding saturns and psx's and whatnot. However the following directions seem to stump me:

Solder pin 2 to hole 24 (A16)
Solder pin 24 to GND (OE)
Solder pin 30 to hole 1 (A17)

I can do the wiring and soldering. But here's what I can't seem to grasp.

I know where the pins are but...

where's hole 24/A16? - is one label easier than the other to find?
how do I know where the GND spots are?
same with hole 1/A17

any help?

-AB+

MottZilla · Post by **MottZilla** » Tue Oct 21, 2008 9:04 am

I think that Flash (5v) might not need an AC adapter, but EPROMs take 12v to program so I think you would still need a AC adapter for them.

Holes refer to the Hole the ROM leg/pin goes into I would think. You need a cartridge and/or ROM pinout to tell which pins of the ROM are which connection. They should be on the main NESDEV page.

We have a bunch of members that have done this, I'm sure they can elaborate more on this.

AB_Positive · Post by **AB_Positive** » Tue Oct 21, 2008 9:10 am

oooh, yeah. I'll need an AC adaptor... I'm sure the willem page would have the electrical requirments (amperage anyway) - I'm working wtih eproms atm since they're cheaper.

So... when you solder "pin x" to "Hole y" you're really soldering one pin to another? Oh wait... is that why you cut the traces too? If so, I think that fills in a gap in my soldering logic.

This is always my problem, my brain gets steps 1, 2, 5 and 6... and 3 and 4 will make no sense to me, if that makes any sense to anyone else.

-AB+

MottZilla · Post by **MottZilla** » Tue Oct 21, 2008 2:53 pm

Some people cut the board traces and do some rewiring. Other people will bend pins on the EPROM and wire around as needed. It's up to you however you want to connect everything.

I think the best thing is to solder the chip in there without bending any pins. Instead carefully cutting traces and rewiring the board is nicer I think. But you know whatever works for you.

As I said, there are experienced people here, hopefully one will reply with advice. I haven't built any reproduction carts.

kyuusaku · Post by **kyuusaku** » Tue Oct 21, 2008 3:11 pm

You don't need an AC adapter for a USB Willem programmer I don't think, they should have a charge pump circuit to generate the 12.5V.

albailey · Post by **albailey** » Tue Oct 21, 2008 6:18 pm

I've never had luck cutting traces (or attempting to repair them) but thats me.

One of the reasons the instructions sometimes say Hole rather than pin, is that for some boards you are putting a 32 pin eprom where a 28 pin one used to be (for me, I just get a 32 pin donor board). I think some UNROM boards are like this.

For Mini Putt you will be using SLROM. You are probably using 256 KB chips (since they are cheapest) even though the PRG and CHR are only
128 KB. So remember to double up those pieces (in DOS you can do this like this: copy /b theFile /b theFile /b theDestFile ). Don't write 128 KB to a 256 KB chip.

One thing you might consider doing is creating a dev cart and only having to re-wire the socket. This is a good way to find out if you have burned the eproms correctly. If you go that route, don't use the "tooled" sockets, just the cheaper "normal" ones. the legs on the tooled ones cannot be bent without snapping them off.

Al

AB_Positive · Post by **AB_Positive** » Wed Oct 22, 2008 5:47 am

Ohhhkay... see the whole 32-pin thing caught me off guard - I was trying to use a 28-pin chip there... ha ha only for CHR. At least I got practice.

How would one make an all-around dev-cart though? Considering all the mappers... I was thinking of making a socketed version of each board revision (including alternates, I know there's a few revs of MMC1 and MMC3) but this may get kind of silly. Is an all around dev-cart even possible?

For those with the USB version of the willem (where it's purely usb, no parallel connection) how would you up it to 12.5V, or would it happen naturally when you choose 27C256?

-AB+

tokumaru · Post by **tokumaru** » Wed Oct 22, 2008 8:46 am

AB_Positive wrote:Is an all around dev-cart even possible?

Yes, it's called PowerPak.

Other than that, no. But if you use a few different Nintendo-made boards you should be able to run most of the US games. There are tons of UNROM games, and a dev-cart is easy to make (you should also make a UOROM while you're at it). If you make another one out of a complete MMC3 board such as TKROM, most MMC3 games should work. Maybe a CHR-RAM MMC3 cart would be good too. Maybe you could do the same with 2 MMC1 boards. That should get you covered for a lot of games.

Post by **tepples** » Wed Oct 22, 2008 11:45 am

tokumaru wrote:
AB_Positive wrote:Is an all around dev-cart even possible?
Yes, it's called PowerPak.

Check that: It was called PowerPak.

kyuusaku · Post by **kyuusaku** » Wed Oct 22, 2008 2:16 pm

AB_Positive wrote:For those with the USB version of the willem (where it's purely usb, no parallel connection) how would you up it to 12.5V, or would it happen naturally when you choose 27C256?

All EPROM require 12.5V so the VPP pin should always be that high. The DIP switches choose which pin gets the programming voltage.

Banshaku · Post by **Banshaku** » Wed Oct 22, 2008 6:47 pm

tepples wrote:Check that: It was called PowerPak.

I'm just curious about your comment. What do you infer? The powerpak is maybe not suitable for dev purpose? Or he cannot produce them anymore?

I'm still going to make my own dev cart once I can get back my soldering iron (left it abroad). Can't wait.

MottZilla · Post by **MottZilla** » Wed Oct 22, 2008 7:15 pm

tepples wrote:
tokumaru wrote:
AB_Positive wrote:Is an all around dev-cart even possible?
Yes, it's called PowerPak.
Check that: It was called PowerPak.

What do you mean was? What happened?

Roth · Post by **Roth** » Wed Oct 22, 2008 8:39 pm

It will still be available. It's my understanding that bunnyboy has ran out of ciclones and is waiting on a shipment of them. Don't freak everyone out Tepples! ; )

Post by **tepples** » Thu Oct 23, 2008 3:32 am

Roth wrote:It will still be available. It's my understanding that bunnyboy has ran out of ciclones and is waiting on a shipment of them.

Thanks. The whole scheme of a product only being available for 3 days every 90 without any sort of preorder just freaks me out, and it might remind some people of the alleged "engineered shortages" of the Wii console.