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This has been really bugging me.

So bottom line is im making a repro of Rob Vs. Term, using 2 27c301s. Ive used 27c301s and know how to wire them both PRG and CHR.

The problem im having is the game starts up, no problems but im getting graphical artifacts on the side. After some investigation its a scrolling issue. The game has Horizontal mirrioring (from Nestopia). When I run it in nesticle with horizontal scrolling only, I mostly get the issue that my NES is replicating (not 100% but close). When its set to vertical in nesticle, no problems.

It might have been a bad board, so I got a new TSROM board, same problem. Its revision 08 if that means anything. Anyway whats up with this repro?! Has anyone made this game with this issue? I even asked if I can mod it like TSLROM for it to work, but was told thats prob not the issue.

So its not the board, or my wiring. Is it something in the code? Is there a different version of the rom where its fixed?


*EDIT* I found and DL'ed another rom of it. In Nesticle AND the Famirom it notes that it supports FOUR SCREEN mirroring. Altho when split, both roms code is identical. The only difference is the header thats removed.

The mirroring shown by emulators (from the iNES header) doesn't matter for MMC3 (unless it's a specific board that has fixed mirroring, I don think this game needs one of those).

Make sure that the CIRAM A10 output from MMC3 properly goes to CIRAM A10 on the cart edge. It is the only pin that affects the mirroring.

Ive followed the CIRAM 10 before today and for a TSROM the trace disappears under the MMC chip. I cant see where it connects, But pin 10 seems like its not connected to anything...

**EDIT**

That did the trick! I connected the CIRAM and no more problems. But that leads me to another question, how is it that CIRAM cart isnt connected to the mapper for TSROMs???

guitarzombie wrote:how is it that CIRAM cart isnt connected to the mapper for TSROMs???

It is connected - if it wasn't, the MMC3 wouldn't be able to control mirroring (and it most definitely can with that board). It's possible that it connected to the MMC3 from underneath, where you couldn't see it.

I completely examined it. I held it to the light to look at it, and I could even see pin 10 from the back with no trace. When I connected CIRAM 10 to the MMC3, i didnt need to cut any trace.

I opened a TKROM and clearly saw the trace for pin 10 on the MMC3, but not for TSROM. Perhaps its done differently?

I just grabbed my copy of SMB3 (MMC3B(Sharp) on TSROM-07) and measured conductivity from MMC3 pin 10 to cartridge connector pin 22: it's definitely connected.

Maybe you damaged the trace when you swapped out ROMs?

yknow I just did the same thing, and with the TSROM board that I originally had issues with, it WAS connected. Why was it giving me garbled scrolling? The new TSROM board I bought had the same problem, and directly wiring 21 to MMC3 p10 worked.