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Neo geo Kizuna Encounter 4p board

Very nice! Would be down for one of these.
 
Prototypes ordered...

MVS-4P-split.jpg
 
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Update:
I got the remaining parts and assembled the first PCB. Pulling out1/out3 high/low shows that the circuit works in the test menu, I can select the P3/P4 and simulate A/B buttons. Though the bios doesn't detect the 4 player mode.
Right now I am not sure if that is because of a problem in furrtek's schematic or the 161-in-1 cart I'm using.

Some things DO seem to work, though: For example some games use the normal P1, other games use the P3. Some strange things are going on with the start buttons as well... Sigh. I'll need to have a closer look at the photos and the MVS bios...

Could someone with the 4p board and a voltmeter confirm a few things?
- how is the cable wired that goes from the board to the 8-pin connector on the mvs?
- can someone confirm that the 4p detection uses buttons A and B? https://wiki.neogeodev.org/index.php?title=CONTROLLER_SETUP
 
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Just a quick update: I socketed an old MVS cart and plan to write a simple test rom that just reads the controller pins.
 
Does anyone know what I need to look out for when running code on the real hardware? My test program runs in Mame, on my unmodded MVS I boot into a cross hatch screen, on my unibios board I get a black screen.

Edit: As usual, found the problem RIGHT after posting... I am using a 27c160 (because all my 27c800 seem to be broken...), and A20 (A19) is held high from /PORTADRS. Copying the tool into the second half of the EPROM fixes it:
PXL_20210724_210916554.jpg

Now I just need to debug the circuit...

Edit: As far as I can tell furrtek's schematic is correct, and I get similar results to a simulation in mame with the kizuna4p driver. I think the problems point to some short circuits, so I'll have to go through the PCB and see if anything is wrong...
 
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Quick update (you are not forgotten)...
- if I connect a scope and probe the various lines I am getting the correct results
- my test program running on actual hardware only works correctly for the first edge
- I do think I know what the problem is, though I need to order some parts

I had a lot of time and energy taken up by work, and I'll be a bit busy with a family matter, so I'll try to continue with this later this month.

Update: this is how the program works in kizuna4p in Mame:
mametest.PNG


216-p1.zip replaces the program rom of kizuna, if you launch it with kizuna4p mame will emulate the 4p adapter.
 

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It looks like I need to rework the PCB a bit, and get a new revision. Though while probing around yesterday I somehow managed to damage the VRAM, so I need to fix that as well ... sigh.

BTW: I am 99% sure that the problems are timing related, though the HC/HCT should be fast enough up to 50Mhz. Does anyone have an idea what to look out for?
 
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Just wanted to know what the original pcb go for these days ? i might have one in my boxes ^^
 
Bump, to see how things are progressing and if the community can help out at all?
 
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