AMROM to AOROM

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guitarzombie
Posts: 164
Joined: Sat Dec 07, 2013 6:18 pm

AMROM to AOROM

Post by guitarzombie »

Hey guys! Been lurking around here a bit grabbing some info here and there but I have one question I can't seem to find the answer to without directly asking. Im making some repros for my own pleasure and one of the games I wanna make uses an AMROM board (Nightmare on Elm St).

Now my issue is not replacing the PRG but getting it to fit back in the cart because of the resistor in the way. Looking at the AOROM, are these boards interchangeable? Their specs seem to be pretty similar and the AOROM can hold a 32 pin chip which would make modding easier (carts with AOROM: Jeopardy, Double Dare, RC Pro-Am II).

I dont really wanna start cutting up my carts. I did learn about the Konami UNROMs now which awesome. The AMROM seems to be the only one I got left that has that problem. A simple explanation'll do. If theres a lot of wiring and stuff to change AMROM to AOROM ill just cut the cart. Just wondering if they're similar enough to work.
tepples
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Joined: Sun Sep 19, 2004 11:12 pm
Location: NE Indiana, USA (NTSC)
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Re: AMROM to AOROM

Post by tepples »

You can load an AMROM or ANROM game onto an AOROM board. The only real changes made in the later boards are bus conflict avoidance (ANROM, AOROM) and support for 2 Mbit ROMs (AOROM).

Or instead of cutting up a game and rewiring the socket, you could order a ReproPak board from retrousb.com and use that for your BNROM/AOROM games. Add an 8-pin CIC and a 74HC161 and bridge a few solder points, and it will be ready to accept standard UV EPROM or flash memory.
lidnariq
Posts: 11429
Joined: Sun Apr 13, 2008 11:12 am

Re: AMROM to AOROM

Post by lidnariq »

The AOROM 32pin pinout doesn't save you from anything other than not having to rewire the Vcc on pin 32.

Additionally, although irrelevant to the immediate question: some ANROM and AN1ROM games require a lack of bus conflicts, and may not work on a repurposed AMROM or AOROM board.

Regardless, we like to encourage people to use new hardware such as the repropak.
guitarzombie
Posts: 164
Joined: Sat Dec 07, 2013 6:18 pm

Re: AMROM to AOROM

Post by guitarzombie »

Hrm... looks like i'll have to. Thanks!

While we're on a similar topic, I was told that I can use an SGROM PCB board for SNROMs as long as I don't care for saving and using the battery. Is this true? I just wired up Maniac Mansion (SNROM) using Rad Racer (SGROM) and it's not working. I wired it using the SROM diagram (pin 1, 2, 24, 30, 31; 30-1H, 2-24H, 16-24)
tepples
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Location: NE Indiana, USA (NTSC)
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Re: AMROM to AOROM

Post by tepples »

Games that use the SNROM's RAM as work RAM won't work on SGROM. It's not like TSROM, which is TKROM without a battery.
guitarzombie
Posts: 164
Joined: Sat Dec 07, 2013 6:18 pm

Re: AMROM to AOROM

Post by guitarzombie »

Well... that was a waste of a cart and my time haha. BUT thanks for everything!
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nintendo2600
Posts: 367
Joined: Mon Mar 30, 2009 4:40 pm

Re: AMROM to AOROM

Post by nintendo2600 »

I know this is a necrobump but I was wondering about the wiring to get AMROM to support 2mb like an AOROM would. Simply put, to get an AMROM 1mb board converted for use as a 2mb AOROM.
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