Converting MHROM CHR 32k to 64k?
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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.
Re: Converting MHROM CHR 32k to 64k?
You've got to be miscounting pins.
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Re: Converting MHROM CHR 32k to 64k?
Im def not.
Anyway I tried another one with a CNROM 256-161 board, same diagram and got glitchy graphics again, even tho the mirroring is right too... hrm.
Anyway I tried another one with a CNROM 256-161 board, same diagram and got glitchy graphics again, even tho the mirroring is right too... hrm.
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- Posts: 164
- Joined: Sat Dec 07, 2013 6:18 pm
Re: Converting MHROM CHR 32k to 64k?
I tried switching the mirroring, and using D3, D4 and D5 and it was worse. So its def D2 and the graphics are all a mess. Im thinking the chip I got was over erased. Gonna chuck it and try again. I hate when i waste all that time for nothing.
And I gotta figure out how my Super Mario Unlimited is working but with NO sound at all (?!) AND i gotta figure out the MHROM 161 altho i have a feelling it just might not work at all, or i have to disconnect some stuff... at least i got a better understanding now.
And I gotta figure out how my Super Mario Unlimited is working but with NO sound at all (?!) AND i gotta figure out the MHROM 161 altho i have a feelling it just might not work at all, or i have to disconnect some stuff... at least i got a better understanding now.
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Re: Converting MHROM CHR 32k to 64k?
Ok I got it. For the CNROM-161 board, I was right the CHR chip was bad straight from the package. Swapped it, and worked. Now for the MHROM board I couldn't figure out why so I checked the pinout of the 161 I did. I saw that it controls PRGs A15 even tho i wasn't using it. I lifted pin 1 of the prg and poof worked (after I set the mirroring)
Interesting that these games when the mirroring is wrong you get a LOT of glitchy graphics not like, lets say SMB where the game works with fine the graphics but 'loads' them to the screen wrong. So all this time I was thinking those bad graphics were from a bad chip or soldering or whatever.
Anyway I learned something and isn't that the most important? Thanks for the help.
Interesting that these games when the mirroring is wrong you get a LOT of glitchy graphics not like, lets say SMB where the game works with fine the graphics but 'loads' them to the screen wrong. So all this time I was thinking those bad graphics were from a bad chip or soldering or whatever.
Anyway I learned something and isn't that the most important? Thanks for the help.
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Re: Converting MHROM CHR 32k to 64k?
I know the last post was over a year ago, but can you upload a wiring diagram of your work? I'm trying to build a Panesian game and i only got grafic garbage.guitarzombie wrote:Then how is it this wiring diargram
PRG:
Pin 14 (GND) to 161 pin 12
CHR:
Pin 1 (A15) to 161 pin 5.
Works for CNROM-07s to make the CHR 64k when you're grounding the output pin of the 161 and a15 goes to the input? I know this cuz its worked for me.
EDIT! SUCCESS! (Kinda)
I took what you said and looked up the 161 and it made sense, so I did a check on the wiring diagram for the CNROM 256-161 and it seemed like D0 went to A13 and D1 when to A14, so using the 161 I connected D2 to A15 and boom! (I just had to set the mirroring). Great! Now ill get a better understanding of the MHROM.
Re: Converting MHROM CHR 32k to 64k?
Panesian -> CNROM Conversion (mapper 3):
Bend up pin 5 and 12 of 74HC161
Connect pin 5 to D2 of PRG ROM
Connect pin 12 to A15 of CHR ROM
Bend up pin 5 and 12 of 74HC161
Connect pin 5 to D2 of PRG ROM
Connect pin 12 to A15 of CHR ROM