NES Repro Help UNROM , U0ROM (Contra RED Falcon War)

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hidden0
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Joined: Tue Mar 15, 2022 11:00 am

NES Repro Help UNROM , U0ROM (Contra RED Falcon War)

Post by hidden0 »

So i have been researching and not be able to find one source where i can find out all the diagrams or pinout , I did make UNROM game , and NROM , CNROM games , worked fine ,
I have been trying to make Contra RED Falcon War (Rom Hack) , It increases the size to 256k , Instead of 128k , And i read it is not UNROM but U0ROM now , And i am using UNROM PCB and i did made some adjustment.

I lifted pins 1, 2, 24, 30, 31, and 32 on the PRG and
Pin 6 on the 161 and 9 and 10 on the 32.

Pin 1 is NC
Pin 2 to A16 (hole 22)
Pin 24 to GND
Pin 31 and 32 are tied to 5V (hole 28)
Pin 30 is tied to pin 8 of the 32 (3rd OR output)
Pin 17 ties D3 to pin 6 on the 161 (D3)
Pin 11 of the 161 ties Q3 to the 3rd OR input on the 32 (pin 10)
Pin 9 on the 32 is tied to pin 2.

But it didn't work.

I am using m27c801 .
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Ziggy
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Re: NES Repro Help UNROM , U0ROM (Contra RED Falcon War)

Post by Ziggy »

I can't really help you much with NES repros since I'm not very familiar, especially converting one mapper to another. But why are you using a 27C801? That's an 8Mb EPROM, but your ROM is 2Mb (256 KB = 2 Mb). You may have some compatibility problem with your ROM and the donor board you're trying to use, but you may also have an issue with your EPROM. I would think you'd have to take the two highest address lines of the 801 and tie them high, which will effectively turn it into a 2 Mb EPROM. Or else, use a 2 Mb memory.
hidden0
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Posts: 77
Joined: Tue Mar 15, 2022 11:00 am

Re: NES Repro Help UNROM , U0ROM (Contra RED Falcon War)

Post by hidden0 »

Ziggy587 wrote:I can't really help you much with NES repros since I'm not very familiar, especially converting one mapper to another. But why are you using a 27C801? That's an 8Mb EPROM, but your ROM is 2Mb (256 KB = 2 Mb). You may have some compatibility problem with your ROM and the donor board you're trying to use, but you may also have an issue with your EPROM. I would think you'd have to take the two highest address lines of the 801 and tie them high, which will effectively turn it into a 2 Mb EPROM. Or else, use a 2 Mb memory.


I am using 801 cuz it can hold upto 1MB rom , My romfile is Actually 256KB , so its like a quarter size. Using 801 because it has the same pinout . and it is listed in famicom rom software as well.
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