wiring a couple of games using Morgan Johansson patchs

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acidrain97
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Joined: Wed Sep 20, 2017 12:13 pm

wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

I know, load it on a everdrive call it done... No fun in that.

Found a donor cart Dragon Warrior that has all the ingredients, couple of problems. Is there a way to change Dragon Warrior to vertical mirroring? Also not sure of the wiring. Is a SLROM the same as a SAROM? Or is there a better donor cart out there?

SLROM (mapper 1):
PRG socket:
Bend up pins 1, 2, 24, 30 and 31 (or cut tracks)
Solder pin 2 to hole 24 (A16)
Solder pin 24 to GND (OE)
Solder pin 30 to hole 1 (A17)
CHR socket:
Bend up pins 1, 2, 22, 24, 30 and 31 (or cut tracks)
Solder pin 2 to hole 24 (A16)
Solder pin 22 to hole 31 (CE or CHR /A13)
Solder pin 24 to hole 2 (OE or CHR /RD)

Another one of his patches is for VS. Excitebike. It's still mapper 99 but works fine on an NES using an everdrive. Is there anyway this can be put on a cart?

Any help would be appreciated.
THX
Joe
Posts: 650
Joined: Mon Apr 01, 2013 11:17 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by Joe »

acidrain97 wrote: Sun May 28, 2023 4:16 amIs there a way to change Dragon Warrior to vertical mirroring?
Mirroring on both SLROM and SAROM is controlled by the mapper.
acidrain97 wrote: Sun May 28, 2023 4:16 amAlso not sure of the wiring. Is a SLROM the same as a SAROM?
Wiring will be similar, but not exactly the same. The wiki has pinouts that might help. However, SAROM is limited to smaller ROMs than SLROM, so your game might be too big. (You didn't say which game...)
acidrain97 wrote: Sun May 28, 2023 4:16 amAnother one of his patches is for VS. Excitebike. It's still mapper 99 but works fine on an NES using an everdrive. Is there anyway this can be put on a cart?
No games were ever released on a compatible cartridge, you'd have to either build a new cartridge or patch the ROM to work with a different mapper.
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

Actually it was vs. duck hunt.

prg 32k 27c256
chr 16k 27c128

both are 28 pin chips.

Same wiring as a slrom?

As for excitebike tried changing mapper 99 to 1 or 4 game runs but lots of garbled graphics... is there a mapper close to 99 that might work? Sorry i'm a noob at this. Simply trying to learn a few things...

thanx
Joe
Posts: 650
Joined: Mon Apr 01, 2013 11:17 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by Joe »

According to the wiki, for the PRG ROM you'll need to lift pin 1 and wire it to +5V (pin/hole 28); and for the CHR ROM you'll need to lift pins 1 and 27, and wire both pins to +5V (pin/hole 28).

You'll need to modify the ROM to use it with a different mapper; Nintendo never made any cartridges compatible with mapper 99.
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

According to the wiki, for the PRG ROM you'll need to lift pin 1 and wire it to +5V (pin/hole 28); and for the CHR ROM you'll need to lift pins 1 and 27, and wire both pins to +5V (pin/hole 28).

Where in the wiki did you get this? I'm looking not finding it.
Joe
Posts: 650
Joined: Mon Apr 01, 2013 11:17 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by Joe »

This page.

I don't think the wiki mentions it, but the programming pins on EPROMs usually need to be connected to +5V during reads.
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

I'm just trying to understand your logic on this:

from the wiki:
27C64/128/256/512 EPROM pinout

(PRG Rom)
|---------------|
Lift pin| 28| - +5V (soldered to pin/hole)
A12 -|02 27| - A14 [PGM]
A7 - |03 26| - A13 [NC]
A6 - |04 25| - A8
A5 - |05 24| - A9
A4 - |06 23| - A11
A3 - |07 22| - /OE
A2 - |08 21| - A10
A1 - |09 20| - /CE
A0 - |10 19| - D7
D0 - |11 18| - D6
D1 - |12 17| - D5
D2 - |13 16| - D4
GND - |14 15| - D3

(CHR Rom)
|-------------------------------------------|
Lift Pin 28| - Soldered to Pin/hole--|
A12 - |02 | - Lift Pin-------------------|
A7 - |03 26| - A13 [NC]
A6 - |04 25| - A8
A5 - |05 24| - A9
A4 - |06 23| - A11
A3 - |07 22| - /OE
A2 - |08 21| - A10
A1 - |09 20| - /CE
A0 - |10 19| - D7
D0 - |11 18| - D6
D1 - |12 17| - D5
D2 - |13 16| - D4
GND - |14 15| - D3


* |----| (bodge wire)

Is this more or less what you're describing? (It won't format the way I want)

"According to the wiki, for the PRG ROM you'll need to lift pin 1 and wire it to +5V (pin/hole 28); and for the CHR ROM you'll need to lift pins 1 and 27, and wire both pins to +5V (pin/hole 28)."

Sorry it's a crude way of doing displaying things but some of it does not make sense... I'm guessing slrom and sarom are different animals. Also does it matter if you are using 27c128 or 27128's?

I was reading another article on the hacked VS. SMB which used two 27256's and it was a simple drop in replacement. No "C" in the chip's name.

So that's why I'm very very confused.
Joe
Posts: 650
Joined: Mon Apr 01, 2013 11:17 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by Joe »

acidrain97 wrote: Thu Jun 01, 2023 6:22 pmIs this more or less what you're describing?
Yes.
acidrain97 wrote: Thu Jun 01, 2023 6:22 pmAlso does it matter if you are using 27c128 or 27128's?
The wiring is the same, but you'll have to double check the speed rating. If your 27128 is too slow, it won't work.
acidrain97 wrote: Thu Jun 01, 2023 6:22 pmI was reading another article on the hacked VS. SMB which used two 27256's and it was a simple drop in replacement.
It might be; I don't have a SAROM board to check. Rewiring is required on some boards, so rewiring ensures it will work for you.
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

I'll give it a try. I am using M27c256b and nm27c128. Fast enough?

thx
Joe
Posts: 650
Joined: Mon Apr 01, 2013 11:17 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by Joe »

Those chips are available in different speeds. The speed rating will be marked as a number (typically) following the part number.

Ideally, you want 275ns or less for the PRG ROM and 175ns or less for the CHR ROM. According to datasheets I was able to find, the M27C256B was manufactured with speed ratings between 45ns and 250ns, and the NM27C128 was manufactured with speed ratings between 90ns and 200ns. The M27C256B will be fast enough to use as your PRG ROM. The NM27C128 might not be fast enough for CHR ROM if it's rated for 200ns.

(And this assumes your EPROMs aren't damaged, excessively worn, or counterfeit...)
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

Got VS. Duck Hunt to fire up... Zapper/coining up etc work great. The only thing not working is the highscore table. Printing as some random character. Scores or 660660. I have seen something like that on VS boards with corrupt memory. Pulled the battery same thing. Emulator shows the highscore table, etc. Could it be the work ram is getting corrupt? Is there a way to find out what actual work ram the game is using via emulator?

thanx
acidrain97
Posts: 12
Joined: Wed Sep 20, 2017 12:13 pm

Re: wiring a couple of games using Morgan Johansson patchs

Post by acidrain97 »

I've given up on Duck Hunt fully working...

Here's the strange thing. I used a couple of 27c512 10f1 100ns burned vs. Home SMB runs fine. High scores/dips settings save fine. Duck hunt did show a proper high score table for all of 2 secs then went back to some funny character.

Dunno this stuff is just beyond me... back to the everdrive... Thanx for the help.
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