UNROM -> AOROM conversion (mapper 7) Question

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.
Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

UNROM -> AOROM conversion (mapper 7) Question

Post by Tormenter » Thu Jul 27, 2006 12:53 pm

I know you can convert an Unrom/Mapper 7 cart (7 - 74HC32). I am attemping to make a Goonies 1 cart. But the problem is, There is both a PRG AND CHR file with this, but the AOROM conversion only talks about the PRG chip slot. Any clues? Thanks Bunches.
Last edited by Tormenter on Fri Jul 28, 2006 12:28 pm, edited 1 time in total.

User avatar
kyuusaku
Posts: 1665
Joined: Mon Sep 27, 2004 2:13 pm

Post by kyuusaku » Thu Jul 27, 2006 5:23 pm

AOROM which is mapper 7 doesn't have a 7432 (OR gate) because it has no static bank.

Goonies 1 is a CNROM in the US AFAIK

AOROM doesn't have CHR ROM, it has CHR RAM.


To convert a UNROM (must be 128kb) to AOROM (must be 256kb) you must simulate a static bank by dividing the game into 16kb blocks and append the last bank (bank 7) to each of the banks including bank 7. The file size should be 256kb. You must then modify the AOROM board by cutting the line from D4 of the 74161 and solder that line (VRAM A10) to CHR A10 if it has vertical mirroring (horizontal scrolling) or CHR A11 if it has horizontal mirroring (vertical scrolling)

Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

Post by Tormenter » Thu Jul 27, 2006 5:34 pm

kyuusaku wrote:To convert a UNROM (must be 128kb) to AOROM (must be 256kb) you must simulate a static bank by dividing the game into 16kb blocks and append the last bank (bank 7) to each of the banks including bank 7. The file size should be 256kb.


.....you lost me. lol Im not that technical into these type of things.

The PRG is 32k, and the CHR is 16k.


So I would use the CNROM board then correct? Even though it says goonies is "Memory Mapper: 7 - 74HC32?"

And CNROMS require no modifications per http://nesdev.com/NES%20EPROM%20Conversions.txt

Even though it states CNROM is mapper 3? Im confused lol. Thanks!

User avatar
kyuusaku
Posts: 1665
Joined: Mon Sep 27, 2004 2:13 pm

Post by kyuusaku » Thu Jul 27, 2006 5:56 pm

Who said Goonies was mapper 7? and who said mapper 7 even had a 7432? Mapper 2 (UOROM) has a 7432 and 74161, mapper 7 only has a 74161.

Yes Goonies is CNROM aka mapper 3. That's right, you won't need to modify the board in any way, just swap out the ROMs.

Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

Post by Tormenter » Thu Jul 27, 2006 5:57 pm

This is what it says in cajoNES anyways. (or the rom I have is) Is this not a correct one?

Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

Post by Tormenter » Thu Jul 27, 2006 6:02 pm

found another copy that says 3 - VROM switch ???

User avatar
Memblers
Site Admin
Posts: 3884
Joined: Mon Sep 20, 2004 6:04 am
Location: Indianapolis
Contact:

Post by Memblers » Thu Jul 27, 2006 6:20 pm

Tormenter wrote:found another copy that says 3 - VROM switch ???
That's the one you want, then. Wow, "VROM Switch", haven't seen that term in a while. I think that's what NESticle called mapper #3 (CNROM).

User avatar
Bregalad
Posts: 7951
Joined: Fri Nov 12, 2004 2:49 pm
Location: Chexbres, VD, Switzerland

Post by Bregalad » Fri Jul 28, 2006 12:37 am

The first Goonies game has been only released in Japan officially, using a discrete logic maper made by Konami, similar to CNROM, but using its register in $6000 range instead of $8000-$ffff

There is a hack of it using mapper 3 floating arround, that avoid bus conflicts correctly, so it can be used on a real mapper 3 hardware.
Useless, lumbering half-wits don't scare us.

Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

Post by Tormenter » Fri Jul 28, 2006 1:54 pm

Would it matter if it was a CNROM-256-05 (Tiger Heli) or a CNROM-06 (Back to the Future) or is there a difference??

User avatar
Bregalad
Posts: 7951
Joined: Fri Nov 12, 2004 2:49 pm
Location: Chexbres, VD, Switzerland

Post by Bregalad » Sat Jul 29, 2006 10:54 am

Look yourself for differences. Normally there shouldn't be much difference, but the solder pads can be different for mirroring and PRG/CHR repeating.
Useless, lumbering half-wits don't scare us.

Tormenter
Posts: 303
Joined: Sat Jun 03, 2006 9:17 pm

Post by Tormenter » Sun Jul 30, 2006 5:24 am

Bregalad wrote:Look yourself for differences.
I tried, hince, thats why I am asking. Im not a techie.

User avatar
Bregalad
Posts: 7951
Joined: Fri Nov 12, 2004 2:49 pm
Location: Chexbres, VD, Switzerland

Post by Bregalad » Sun Jul 30, 2006 1:47 pm

Well, you don't need to be that much technical. Just look the PCB and notice what is different on them. Sometimes there is minor details, such as additionnal capacitors or resitsorts that have some noise-immunity issues, or solder pads that are different (this is significant for Name Table mirroring). Other than that, most difference between PCB variants are unsignificant.
Useless, lumbering half-wits don't scare us.

cardiff
Posts: 9
Joined: Wed Feb 12, 2020 3:14 pm

Re: UNROM -> AOROM conversion (mapper 7) Question

Post by cardiff » Thu Mar 19, 2020 9:00 am

I 've been trying to make Battletoads Famicom for days.
I removed '32
Lifted 6 pin '74 and connected to 18 pin 27c020
Connected 11 pin '74 to 18 pin cartridge (CIRAM A10)
Connected 3 pin 27c020 to 11 pin '74
Connected 2 pin 27c020 to 13 pin '74
Connected 30 pin 27c020 to 12 pin '74
Connected 24 pin 27c020 to 16 pin 27c020
Connected 1 pin 27c020 to hole 1 pin prg
But nothing works. Where did I make a mistake?

Ice Man
Posts: 546
Joined: Fri Jul 04, 2014 2:34 pm

Re: UNROM -> AOROM conversion (mapper 7) Question

Post by Ice Man » Thu Mar 19, 2020 1:01 pm

Why are you using a 74'74? AxROM does not have any but a 74'161 (and eventually a 74'02 for ANROM).

Either way, here's the pinout:

Code: Select all

                    74'161                          74'02 (ANROM only)
                    __  __                          __  __
               VCC |01\/16| VCC               1-12 |01\/14| VCC
           /ROMSEL |02  15| NC             CPU R/W |02  13| 8-9-13
            CPU D0 |03  14| PRG A15         PU R/W |03  12| 1-12
            CPU D1 |04  13| PRG A16             NC |04  11| /ROMSEL
           CPU D2* |05  12| PRG A17*           GND |05  10| PRG /CE*
            CPU D4 |06  11| CIRAM A10          GND |06  09| 8-9-13
               GND |07  10| GND                GND |07  08| 8-9-13
               GND |08  09| CPU R/W                 ------
                    ------


*
AMROM:
CPU D2  = Connected
PRG A17 = Not Connected
PRG /CE = Not Connected

ANROM:
CPU D2  = Not Connected
PRG A17 = Not Connected
PRG /CE = Connected

AOROM:
CPU D2 	= Connected
PRG A17 = Connected
PRG /CE = Not Connected

cardiff
Posts: 9
Joined: Wed Feb 12, 2020 3:14 pm

Re: UNROM -> AOROM conversion (mapper 7) Question

Post by cardiff » Thu Mar 19, 2020 2:42 pm

Ice Man wrote:
Thu Mar 19, 2020 1:01 pm
Why are you using a 74'74? AxROM does not have any but a 74'161 (and eventually a 74'02 for ANROM).

Either way, here's the pinout:

Code: Select all

                    74'161                          74'02 (ANROM only)
                    __  __                          __  __
               VCC |01\/16| VCC               1-12 |01\/14| VCC
           /ROMSEL |02  15| NC             CPU R/W |02  13| 8-9-13
            CPU D0 |03  14| PRG A15         PU R/W |03  12| 1-12
            CPU D1 |04  13| PRG A16             NC |04  11| /ROMSEL
           CPU D2* |05  12| PRG A17*           GND |05  10| PRG /CE*
            CPU D4 |06  11| CIRAM A10          GND |06  09| 8-9-13
               GND |07  10| GND                GND |07  08| 8-9-13
               GND |08  09| CPU R/W                 ------
                    ------


*
AMROM:
CPU D2  = Connected
PRG A17 = Not Connected
PRG /CE = Not Connected

ANROM:
CPU D2  = Not Connected
PRG A17 = Not Connected
PRG /CE = Connected

AOROM:
CPU D2 	= Connected
PRG A17 = Connected
PRG /CE = Not Connected
Sorry I was wrong while I wrote. Of course I use 74 '161

Post Reply