NES Willem EPROM writing issues

A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.

Moderators: B00daW, Moderators

Forum rules
1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.
Post Reply
GamingWithSkippy
Posts: 4
Joined: Mon Oct 17, 2016 12:48 am

NES Willem EPROM writing issues

Post by GamingWithSkippy » Mon Oct 17, 2016 12:55 am

So I have every thing I need for programming repros for my self. But I have run in to some thing of a snag.

I use Famirom to split the rom. I have the correct mirroring. The correct size eproms. But every single REPRO I try to burn turns out the same. I have tried 7 different boards, the donors have worked before taking the rom chips off. ( Bandai Golf is a dime a dozen CN-ROM )

Am I doing some thing wrong? Or is my Willem just pooched?

I have attached photos of the outcome.

1 of the cart, and one of what shows on the TV when i load the Cart to the NES..... I am stumped.
Attachments
IMG_0478.JPG
IMG_0480.JPG

User avatar
Memblers
Site Admin
Posts: 3802
Joined: Mon Sep 20, 2004 6:04 am
Location: Indianapolis
Contact:

Re: NES Willem EPROM writing issues

Post by Memblers » Mon Oct 17, 2016 1:20 am

I seem to recall that ST EPROMs required VCC to be 6.5V when programming, and at least on the Willem 3.5 PCB (the one I had) that required setting a jumper. But if they verify in the programmer, then the programmer is fine and VCC voltage is probably not the issue.

Those EPROMs, at least the PRG I can see the part number, are 64kB ROMs. While CNROM is 32kB. If A15 is connected to 5V, that means you need to put the 32kB data in the upper half of the EPROM (it's just as well to double-up the ROM data before burning it). So it could be that.

User avatar
thefox
Posts: 3141
Joined: Mon Jan 03, 2005 10:36 am
Location: Tampere, Finland
Contact:

Re: NES Willem EPROM writing issues

Post by thefox » Mon Oct 17, 2016 1:20 am

Wrong forum.
Download STREEMERZ for NES from fauxgame.com! — Some other stuff I've done: fo.aspekt.fi

lidnariq
Posts: 9138
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: NES Willem EPROM writing issues

Post by lidnariq » Mon Oct 17, 2016 11:57 am

The screen is full of random tiles, in a variety of different shades.

This means that:
CHR ROM appears to be working correctly
PRG ROM is working far enough to upload a palette and enable rendering
The CPU then crashes.

The possible failure modes are (AFAIK):
the PRG UVEPROM is damaged
the PRG is miswired
the game downloads content from CHR and that's not working correctly.

GamingWithSkippy
Posts: 4
Joined: Mon Oct 17, 2016 12:48 am

Re: NES Willem EPROM writing issues

Post by GamingWithSkippy » Mon Oct 17, 2016 1:17 pm

lidnariq wrote:The screen is full of random tiles, in a variety of different shades.

This means that:
CHR ROM appears to be working correctly
PRG ROM is working far enough to upload a palette and enable rendering
The CPU then crashes.

The possible failure modes are (AFAIK):
the PRG UVEPROM is damaged
the PRG is miswired
the game downloads content from CHR and that's not working correctly.

This is what confuses me. I have tried out multiple boards and many eproms just to get the same thing every time. It can't be like this for 7 different boards and 7 sets of eproms...... Or can it?

lidnariq
Posts: 9138
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: NES Willem EPROM writing issues

Post by lidnariq » Mon Oct 17, 2016 2:07 pm

I suppose if you're always making the same rewiring mistake, it could be the same regardless of PCB...

But it's a CNROM board and game so I'm kinda confused by that.

GamingWithSkippy
Posts: 4
Joined: Mon Oct 17, 2016 12:48 am

Re: NES Willem EPROM writing issues

Post by GamingWithSkippy » Tue Oct 18, 2016 11:57 am

Yeah, because CN-ROM boards don't require any re-wiring.

lidnariq
Posts: 9138
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: NES Willem EPROM writing issues

Post by lidnariq » Tue Oct 18, 2016 12:23 pm

On the off-chance ... is there any possibility that the mirroring jumper is wrong and the game is crashing waiting for a sprite 0 hit?

GamingWithSkippy
Posts: 4
Joined: Mon Oct 17, 2016 12:48 am

Re: NES Willem EPROM writing issues

Post by GamingWithSkippy » Tue Oct 18, 2016 1:29 pm

I figured it out. It was my own stupidity. I had the option [ Skipt Write 0xFF ] Checked off. That there could screw up any thing. I got it working though.

Thank you every one for your suggestions! I also had the EPROM under volted!

REJOICE! GWS Rom hacks on Carts!
Attachments
IMG_0187.JPG

Post Reply