CRT Emudriver - Sync Issue

[DJO_Maverick]

I'm trying to transition to a Groovymame/PC based setup for my cab, and am having some pains getting the emudriver working right.  I'm suspicious it's a cable issue, but would appreciate a second opinion before I start buying even more cords.

I'm using an R7 350x (so one DVI-I and one DP output), using a generic DVI-I-to-VGA converter, and then hooking it up to the CRT with an Ultimate Mister VGA/SCART cable (https://ultimatemister.com/product/rgb-scart-cable/).  It warns off alternate uses because of its wiring, but I believed (maybe mistakenly) that outputting CSYNC would make it suitable. 

I get through all setup using a straight VGA from the dongle to an old analog flat panel monitor, then it behaves as expected when EDID Emu is turned on (the flat panel reports out of spec, and I can then hook it up to a CRT and get a picture), but it's got sync issues...  both on a big JVC (using a SCART-to-Component Retrotink), and a PVM (using a SCART breakout). 

With CSYNC disabled, the picture looks substantially correct, with a loss of vsync.  It's a slow-roll on the JVC (slow enough to at least navigate menus still), and actually a much faster v-roll on the PVM.  However, with CSYNC enabled, things get really wild.  On the PVM, both horizontal and vertical sync are gone.  On the JVC, it gives the illusion of partially holding depending on the window on the screen, but quickly goes nuts trying to move anything...  definitely out of both H/V sync.

As an aside, kinda surprised my PVM is less tolerant than the JVC.

Is that cable wired wrong for Emudriver's CSYNC?  Any different recommendation?  Or do I need something like a VGA2SCART sync converter?  I was thinking that the CSYNC output feature would dodge the need for one of those.

Thanks,

[Zebidee]

You definitely have sync issues.

As you suspected already, the biggest unknown is the Ultimate Mister VGA-SCART. The website itself warns that the cable is designed for use with Mister only. In particular I notice that RGB autoswitching (pin 16) is weird, relying on 1.6v via VGA pin 14 (which corresponds to vertical sync).

https://ultimatemister.com/product/rgb-scart-cable/

What's wrong with this is that PCs do not output 1.6v via pin 14. RGB TVs require a RGB switching signal around 1.0-3.0v. PCs output more like 3.5v to 5.0v via pin 14. Also, when you enable CSYNC in CRT_emudriver, your PC will output *nothing* via VGA pin 14/Vertical sync, so the RGB switching (for your JVC, at least) will not work.

Your JVC will require a RGB switching signal from the VGA-SCART cable. If you want to hack the cable, easiest way to achieve this is taking 5v (via pin9 or via MOLEX from PC) and running that through a ~150-200R resistor to reduce voltage to ~2.0v, and running that into SCART pin 16 instead.

Regarding software setup, and if switching CSYNC on/off via VMMaker, you should regenerate and re-install the video modes. Otherwise it won't work right. Hopefully this will be good enough to enable the Retrotink unit to work, at least.

If the retrotink still doesn't work,  then I suggest you try a GreenAntz VGA to RGB transcoder instead. GreenAntz has some advantages vs Retrotink, especially because you don't have to worry about sync, it handles that all for you.

With a GreenAntz, you won't even need a VGA-SCART cable for your component TV. GreenAntz connects your PC to (component) CRT-TV directly, using common/generic/cheap/easily available cables.

More on GreenAntz here: http://forum.arcadecontrols.com/index.php/topic,164245.0.html

You can only get GreenAntz directly from me, but it will be cheaper than the advertised Retrotink price.

If you want/need, I could also make a bespoke VGA-SCART cable to you, that should work with your JVC setup. This would be "reasonably priced" - more expensive than your Mister VGA-SCART cable, but it will be custom-made for your needs and should work. PM me directly for any GreenAntz transcoder and/or VGA-SCART cable requests.

Note that I can't process any orders until April, as am traveling right now.

Good Luck!
Z.

[DJO_Maverick]

Thanks;

So the few things that I guess I'm still fuzzy and seeking understanding on:

- If it's a not native RGB/SCART TV that's only getting component fed via the Tink transcoder...  why is the switching signal an issue?  In that vein, since PVMs don't require such a signal, why would the loss of that pin signal be causing the PVM to exhibit the same behavior change?

- Somewhere in your GreenAntz thread, you mentioned that once you started supporting composite sync, allowing it to work with DVI-VGA dongles.  Well, I definitely have to use a DVI-I-to-VGA dongle with this card.  Is that to suggest that the average dongle is already combining sync?

- So with CSYNC turned off, it appears to be getting functional Hsync, which makes sense with the pin-out and the cable (VGA 13 to SCART 20).  I thought Csync combined Hsync and Vsync, which should still be going to pin 20...  so why would it freak out if Csync got output there?  Is it the attenuation on that pin in that particular cable?  Or does Emudriver pump Csync to pin 14 (Vsync) instead?

As an afterthought, most likely unrelated, I've also got the issue where VMM always lists me as having something like 18 different displays even though there's only one output being used...  feel like I've read about that somewhere but didn't catch a solution.

[Zebidee]

- If it's a not native RGB/SCART TV that's only getting component fed via the Tink transcoder...  why is the switching signal an issue?  In that vein, since PVMs don't require such a signal, why would the loss of that pin signal be causing the PVM to exhibit the same behavior change?

I'm not sure why, or even if, the switching signal is an issue for the retrotink. The issues seem to relate to the sync. Maybe the sync signal is too high for it. Maybe it'll work OK if you re-generate and re-install the video modes after enabling Csync.

- Somewhere in your GreenAntz thread, you mentioned that once you started supporting composite sync, allowing it to work with DVI-VGA dongles.  Well, I definitely have to use a DVI-I-to-VGA dongle with this card.  Is that to suggest that the average dongle is already combining sync?

At the time I wrote that, I believed you could only get composite sync out via a DVI-VGA dongle. This was because there are 4 analogue pins which sit separately on one side of the DVI end for RGB+Hsync/Csync. However, here is where I admit that I was wrong, sorry about that. There actually is a Vsync pin in the main bunch of DVI pins too. So, you CAN get H+V sync out via the dongle. I've edited my previous post and removed that comment.

- So with CSYNC turned off, it appears to be getting functional Hsync, which makes sense with the pin-out and the cable (VGA 13 to SCART 20).  I thought Csync combined Hsync and Vsync, which should still be going to pin 20...  so why would it freak out if Csync got output there?  Is it the attenuation on that pin in that particular cable?  Or does Emudriver pump Csync to pin 14 (Vsync) instead?

Your assumptions here are correct, Csync will be output via the Hsync pin 13 -> SCART 20. So why does it freak out? I can only guess that there is a problem with the csync generation, so try re-generating and re-installing the modes.

[DJO_Maverick]

So I went back and tried a couple more times, this time specifically regenerating modelines and reinstalling them after turning on comp sync...  same effect.

For sake of completeness, I went and changed the polarities to positive (even though it's not a legacy card) just to see, and regenerated and reinstalled modes once more.  Looks identical.


Note it's a generic default Win10 layout, so it ought to be blue...  the comp sync issue is causing color distortion as well (the obvious red shift).  The black band isn't visible to the naked eye but you can see a bit where it's clearly out of sync in the upper right and the lower right, even though it gives the illusion of v at least holding, until you try moving much around on the screen.  And again, with comp OFF, the picture looks entirely fine, except for V rolling.

Thoughts?

[DJO_Maverick]

For anyone who encounters the same, ended up resolving issues by giving up on software generated C-Sync and just grabbing a VGA-Scart cable from Retrocables.es that has the sync combiner integrated. 

No clue why my system just never could cooperate with the emudriver C-Sync, but all set now.

[Zebidee]

Now I'm not travelling, I had a fresh look at this thread.

I think the issue with your first cable, the "Ultimate" MiSTer VGA to RGB SCART Cable, is that it is based on gambaman's designs for "The ultimate VGA to SCART adapter", which are detailed here:
http://forum.arcadecontrols.com/index.php?topic=160869.0

This cable requires 5v from VGA pin 9 to manage the composite sync, which will not be available if you are using a DVI-VGA dongle. This not only means that the onboard chip to process the sync won't work, but also it will block any sync signals from getting through passively.

I assume that your new cable comes with a molex (4 pin) cable/header to get power from the PC? Like this one?
https://retrocables-es.translate.goog/tienda/index.php?id_product=442&controller=product&id_lang=4&_x_tr_sch=http&_x_tr_sl=es&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc

[DJO_Maverick]

I assume that your new cable comes with a molex (4 pin) cable/header to get power from the PC? Like this one?

No, it's this one.  http://retrocables.es/tienda/index.php?id_product=55&controller=product&id_lang=1
However, I'm not using the USB power, it's running fine in pure passive.

[psakhis]

This cable is "normal", so don't have any micro to generate csync. Just it's combining h+v signals.

[Zebidee]

Fortunately the SCART input 'Tink device won't care about RGB switching, so won't need power. you'd only need power for SCART TV RGB and/or AV switching.

I wonder if the SCART cable just has H+V syncs twisted together and through a resistor? Simple yet works in many/most cases.