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Irken (MiSTer) JAMMA Expander

invzim

invzim

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Being intrigued by the recent developments in MiSTer, and also recently getting a Sega Aero City - I'm working on a JAMMA board for DE10-Nano. It's a bit of re-use from other projects, and some new stuff. Main difference from other (announced and available) projects is the use of HDMI - this one has an on-board HDMI->VGA and HDMI->AUDIO DAC, instead of depending on GPIO pins. This is to get the best quality, and also keep things simple - at least in theory.

If you've seen the the other stuff I make, this one has a few similarities - it has the OLED and micro-sd firmware update.

2021-03-20 j-expander.png
 
I specifically only bought one MiSTercade because I saw your MiSTer/Aero City comment and was hoping you had something like this up your sleeve.

Big fan of all your other products (have several of each) and can't wait to grab one of these too!
 
seeing that B6/GND @ edge 27 + the CPS2 I must ask:

- If the CPS2 is used, what happens to GND and B6?
 
I assume you’re going to use the MiSTer’s Direct Video with the HDMI output to minimize latency?
 
Mrhide said:
- If the CPS2 is used, what happens to GND and B6?
Click to expand...
The whole package doesn't draw more than ~1.5A max, so I figured I could spare a GND pin and make it "chamma" compatible. You get button 6 on both JAMMA edge and kick.

ShootTheCore said:
I assume you’re going to use the MiSTer’s Direct Video with the HDMI output to minimize latency?
Click to expand...
Yup, direct_video is the driving tech behind this board.
 
When do you think this will be available? :) Norway is a lot closer than the US
 
invzim said:
o I figured I could spare a GND pin and make it "chamm
Click to expand...

Rebuilding a tekken5 cab, I have been cheap and used a "chamma" loom with a capcom JVS IO and this is what's happening:

Since JAMMA does have ground @ edge 27, that 6th button is ON on jamma! Soul Caliber 3, with the capcom IO, was unplayable cause everytime I would hit a button, it would be as if I had hit the 6th button, and the character would do its long charge move, allowing for the opponent to kick my arse.

After trying a few things, I realized what was happening and "fixed" it but inserting a connector for both 6th buttons from the jamma connector. If I want chamma (...why would I?), I connect it, if I don't, I unplug it:

system 246, capcom IO, CHAMMA:
IMG_6403.jpg

IMG_6404.jpg


same system, unplugged (so jamma)

IMG_6406.jpg

IMG_6405.jpg



anyway, you probably knew this and I am not sure it applies to the MisTer but there you have it.
 
Mrhide said:
anyway, you probably knew this and I am not sure it applies to the MisTer but there you have it.
Click to expand...
I can check if pin 27 is connected to GND, if it is - it should be safe to assume the cab is normal JAMMA. If it's not connected to GND, it's either a crappy jamma harness or chamma cab.
 
It looks great. If it's compatible with the design I'd keep the TOSLink connector for those who want to use a custom DAC like the Topping E30.

I'm curious about the video DAC, does it support full range?. I see potential in a simple and well done full range HDMI to VGA DAC boards too.
 
pacoarcade said:
It looks great. If it's compatible with the design I'd keep the TOSLink connector for those who want to use a custom DAC like the Topping E30.

I'm curious about the video DAC, does it support full range?. I see potential in a simple and well done full range HDMI to VGA DAC boards too.
Click to expand...
A TOS link would be out-of-scope for this thing, I don't think any jamma boards use that. and I don't want the associated support The audio DAC on this board is not like the IO board, i.e. it's a proper IC. If you really want a TOS link, you can put an IO board on top of the DE10, as the jamma expander doesn't use any GPIO pins.

Video DAC supports full range. You can pick up full range HDMI-VGA dongles for 2 USD on AliExpress :)
 
invzim said:
I figured I could spare a GND pin and make it "chamma" compatible. You get button 6 on both JAMMA edge and kick.
Click to expand...

Windy and Egret 2 cabs use 27/e for the control grounds. Without it connected to ground the controls will not work.

Nothing a scalpel and solder cant fix though. ;)
 
yosai said:
Windy and Egret 2 cabs use 27/e for the control grounds. Without it connected to ground the controls will not work.
Click to expand...
In that case I will probably leave button 6 for the kick - I don't want to encourage chammafication :)
 
Small update, had to swap out the audio amp to an ancient one as the speaker cables inside the cab interfered with the video - lesson learned on that one, spent quite some time debugging the video system only to find out it had nothing to do with video on the PCB at all :P

I'm implementing a much simpler software version of the sync analytics found in the A1 scaler, to both debug issues and to protect the CRT - i.e. if for some reason MiSTer is outputting any non-jamma frequencies, they will be blocked by the Expander.

A new proto PCB is in transit, and with a bit of luck I should have something working next week-end.
 
I've never used a MiSTer before, but I'd love to throw one of these into my blast city.
 
I'll definitely be getting one of these. I picked up a Mister last week (thanks for the help setting it up @pubjoe ) and have been using an @invzim JVSPAC2 to connect it to my Windy 2 (thanks for the config guide) that makes it a nicely supported plug 'n' play device.

The expander will make it nicely plug 'n' play in my Astro 8)
6496efad-54ff-415d-9bab-ef4c7640e08f.jpg

d2886040-2ccd-4629-9cd7-c56b4545cfba.jpg
 
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