EPROM Pin Swapper

A place where you can keep others updated about your NES-related projects through screenshots, videos or information in general.

Moderator: Moderators

User avatar
FARID
Posts: 499
Joined: Wed Apr 07, 2010 1:14 am
Location: Iran
Contact:

EPROM Pin Swapper

Post by FARID »

Image

Download EPROM Pin Swapper v1.0

Virus Total : 0 / 43

Currently support for :
27C010
27C020
27C040
27C080

Source code is also included, it is in VB6.
There are a lot of bugs in it, use it at your own risk.
User avatar
koitsu
Posts: 4201
Joined: Sun Sep 19, 2004 9:28 pm
Location: A world gone mad

Post by koitsu »

Given the screenshot, what exactly is it "swapping"? All I see is a pinout of an EPROM which lets you adjust what each pin is assigned to. You can't change the functions of an EPROM pin, so why are the pins changeable?

I think I may be misunderstanding because I envision the program to be something that converts the pinouts between two types of chips. For example, mask ROM <-> 27C080, or mask ROM <-> 2mbit EEPROM. You get the idea. And for that to work, you'd really need to show two chips and a chart (either wiring diagram, or "pin 1 of mask ROM --> pin 7 of EEPROM", you get the idea.

What am I missing here?
User avatar
MottZilla
Posts: 2837
Joined: Wed Dec 06, 2006 8:18 pm

Post by MottZilla »

I think it can swap address lines and data lines by reorganizing the ROM data.
User avatar
infiniteneslives
Posts: 2104
Joined: Mon Apr 04, 2011 11:49 am
Location: WhereverIparkIt, USA
Contact:

Post by infiniteneslives »

Very nice! I always just thought about doing this physically with the programmer pins assuming you weren't using flash. But just rearranging the ROM makes a lot more sense.
User avatar
MottZilla
Posts: 2837
Joined: Wed Dec 06, 2006 8:18 pm

Post by MottZilla »

With a few Nintendo pinouts address lines actually are swapped compared to standard eproms so doing this saves you rerouting a few pins. On SNES with 27c801s you can use that swapbin to only have to rewire something like 2 or 3 pins.
User avatar
nintendo2600
Posts: 367
Joined: Mon Mar 30, 2009 4:40 pm

Post by nintendo2600 »

awesome!
User avatar
jpx72
Posts: 178
Joined: Tue Sep 28, 2010 3:27 am
Location: Slovakia
Contact:

Post by jpx72 »

Wow that IS awesome!!!
Karatorian
Posts: 76
Joined: Sun Sep 30, 2007 9:54 pm
Location: Corneria
Contact:

Post by Karatorian »

Definitely a cool idea. Seems to work perfectly under Wine as well.
User avatar
jpx72
Posts: 178
Joined: Tue Sep 28, 2010 3:27 am
Location: Slovakia
Contact:

Post by jpx72 »

How hard would be to implement also exchanging Data with Adress lines? It's a chunk of data being reorganised, so there must be an algorythm to allow this change... Hmm?
User avatar
l_oliveira
Posts: 409
Joined: Wed Jul 13, 2011 6:51 am
Location: Brasilia, Brazil

Post by l_oliveira »

jpx72 wrote:How hard would be to implement also exchanging Data with Adress lines? It's a chunk of data being reorganised, so there must be an algorythm to allow this change... Hmm?
Swapping data pins with addresses is impossible simply because data pins are outputs and address pins are inputs.
User avatar
Punch
Posts: 365
Joined: Sat Feb 16, 2013 11:52 am

Re: EPROM Pin Swapper

Post by Punch »

How does this work anyway? Awesome piece of software, didn't knew that was possible
This is a block of text that can be added to posts you make. There is a 255 character limit.
User avatar
l_oliveira
Posts: 409
Joined: Wed Jul 13, 2011 6:51 am
Location: Brasilia, Brazil

Re: EPROM Pin Swapper

Post by l_oliveira »

Punch wrote:How does this work anyway? Awesome piece of software, didn't knew that was possible
It just reorganizes the rom image file so you can swap out how the pins on the eprom (for purposes such as simplify board layout) are connected to the host system, while keeping the final result (data being read) same as if the eprom was connected in the normal way.

As it was mentioned on the thread, the only reason to do this is save time/effort on board layout.
User avatar
blargg
Posts: 3715
Joined: Mon Sep 27, 2004 8:33 am
Location: Central Texas, USA
Contact:

Re: EPROM Pin Swapper

Post by blargg »

Imagine you take an EEPROM in circuit and swap the D0 and D1 connections. The NES will get the wrong bits. Now, in the file on the PC, swap these bits, then rewrite the EEPROM. Now the NES gets the right data.

Imagine the same for the address lines. Swap A0 and A1. This causes the NES to read bytes in this order: 0, 2, 1, 3, 4, 6, 5, 7... So just reorder them like this in the file on the PC and rewrite the EEPROM, now the NES gets things correctly.

Similar for rearranging the data pins among each other, and the address pins among each other, just a reordering of bytes/bits within bytes.
User avatar
FARID
Posts: 499
Joined: Wed Apr 07, 2010 1:14 am
Location: Iran
Contact:

Version 1.2

Post by FARID »

Version 1.2
Changes :
Added 29F040
Bug fix for 27C080

Still it is very buggy so use it at your own risk.
Attachments
EPROM_Pin_Swapper_v1.2.zip
(603.14 KiB) Downloaded 41 times
Last edited by FARID on Fri Jun 02, 2023 11:36 am, edited 2 times in total.
wyndcrosser
Posts: 42
Joined: Mon Jul 30, 2012 1:44 pm

Re: EPROM Pin Swapper

Post by wyndcrosser »

Just to confirm. This would like me change the what the pins do, instead of having to re-wire correct?
Post Reply