Gunstar wrote:I wonder if it's worth Rama starting a new thread where he has control of the first post to put all this info in one place, there's lots of useful info and tips scattered through the thread like Syntax splitting the CLK0 pad to better place the optional 1nF cap.
This. I'm freaking confused. The thread clearly is completely different than the write-up in post #1 at this point. It should be broken-off by a mod somewhere and re-introduced or something.
Does GBS-control handle 15kHz output for 240p/480i PVMs?
Quick question: Can the GBS Control accept 480p signals through the D-Sub port? 480p is working great through the component rca jacks, but I'm getting a jumbled image from the D-Sub. Does that input expect 15hkz only?
Yes and no, D-Sub accepts EGA,VGA modes, so required separated sync (V/H) @31.4KHz signal
480p component ≠ 640x480p VGA
It does not require separate syncs (H/V) in fact it works better with composite sync. It does "require" (not really but works better if) you use clean sync. Sync needs to go on the h-sync pin.
While DTV 480p and VESA 640x480 are in fact different in the pixel clock, from a physical "transport layer" perspective they are exactly the same. Either will work on an input expecting the other.
Gunstar wrote:I wonder if it's worth Rama starting a new thread where he has control of the first post to put all this info in one place, there's lots of useful info and tips scattered through the thread like Syntax splitting the CLK0 pad to better place the optional 1nF cap.
This. I'm freaking confused. The thread clearly is completely different than the write-up in post #1 at this point. It should be broken-off by a mod somewhere and re-introduced or something.
Does GBS-control handle 15kHz output for 240p/480i PVMs?
maxtherabbit wrote:
It does not require separate syncs (H/V) in fact it works better with composite sync. It does "require" (not really but works better if) you use clean sync. Sync needs to go on the h-sync pin.
While DTV 480p and VESA 640x480 are in fact different in the pixel clock, from a physical "transport layer" perspective they are exactly the same. Either will work on an input expecting the other.
Component video won't work on the VGA input
You tell me that the GBS82xx requires "just to work" on the VGA input,
"only" the RGB and S (clean or comp sync) signal on the H-sync pin?
I have always used Vsync and Hsync from consoles (if available), I have
never tried to connect only Csync. Does this apply to GBS8xxx or any VGA input, like a CRT VGA monitor?
From my testing GBS Control has trouble with RGBHV sources. If HV is converted to Csync before feeding to GBS, it works fine.
And GBS will always output RGBHV.
hellbelly wrote:Still impressed with this. In fact, it allows me to play my CMVS on my Sony TV which is really picky, couldn’t do this through my OSSC no matter what setting I changed.
Pete
@hellbelly Going a bit off topic here, but did you try these settings on the ossc?
NoAffinity wrote:I've used gbs cfw on cps1 and cps2. I have stability issues through a retrotek supergun., but no problem with direct feed from a cps2 av io (effectively a direct connection from arcade rgbs to gbs and overly bright but that's a separate issue and stability is good.
The retrotek sync line has a 680ohm resistor on it. I swapped for a 470ohm and added a 22uf cap but it didn't make any difference.
I also have no problem going through a mak strike supergun to gbs.
So I suggest it might be ultimately caused by the supergun.
Yeah this, I have no issues with direct connections, but when I use a splitter of any sort, I get problems... Until I used the clock gen. it's still not 100% stable but it rarely jumps now.
Also, is there a way for the GBS to output at arcade monitor RGB levels? I tried the downscale feature using Naomi 31khz to a Nanao MS8 and it works great with a sync combiner before the GBS, except the image is quite dim, similar to a directly connected VGA. I just recalibrate the monitor to make it look ok, but it's not ideal.
NoAffinity wrote:I've used gbs cfw on cps1 and cps2. I have stability issues through a retrotek supergun., but no problem with direct feed from a cps2 av io (effectively a direct connection from arcade rgbs to gbs and overly bright but that's a separate issue and stability is good.
The retrotek sync line has a 680ohm resistor on it. I swapped for a 470ohm and added a 22uf cap but it didn't make any difference.
I also have no problem going through a mak strike supergun to gbs.
So I suggest it might be ultimately caused by the supergun.
except the image is quite dim, similar to a directly connected VGA. I just recalibrate the monitor to make it look ok, but it's not ideal.
Have you adjusted gain using the web ui controls? Mine always starts out dim if I'm not using a saved profile. I turn on auto gain, give it a few seconds, turn off auto gain, then hit gain + a couple times. For most sources, the best setting is around 45. You can just leave auto gain on, but i find it dims in different scenes. Not terribly, but I still prefer it stays at a static setting that is to my liking. Of course once you get everything dialed on a particular source, save a profile. The gbs always restarts on the last selected profile, or if you dont have a saved profile, then it restarts on the last chosen resolution.
Phew, lots of questions, some aren't easily answered :p
CSync vs separate H+V (input to GBS):
Both are supported on the RGBs(HV) port. The Component Video input uses embedded syncs on luma (as per standard) and works well with it.
For the RGBs(HV) port, using CSync is better. The chip can detect formats from CSync, whereas H+V sync requires guesswork.
If you have the option, use CSync. If only H+V is available, try it. It might work just fine.
In stubborn cases, a sync combiner could be used. People have open source designs that can do it, but it can also be done with a couple cheap parts.
"Naomi 31khz to a Nanao MS8 and it works great with a sync combiner before the GBS, except the image is quite dim"
This dim picture may be a configuration issue on the Nanao MS8. If the GBS potentiometers are all the way to the left (or bridged), the picture should be okay out of the box, IF the Nanao MS8 has proper balance and outputs TV level RGB.
"output at arcade monitor RGB levels"
Not with software alone. Maybe an additional video driver chip could do this? I don't think it'll be easy though.
"New thread"
Yes, I know. Big project atm, but I'll get to it eventually :p
So just to verify, CSYNC or HVSYNC can go into the GBSC but the output will always be seperate HV. If I am downscaling to 15Hz to an RGB TV then I will need a sync combiner between the GBSC and the Set/PVM? So will the Sync Blaster work to get the output to the apporiate CSYNC? https://www.retrogamingcables.co.uk/SYN ... B-STRIPPER
I'm going in to the Luma pin on S-Video for sync but could switch to composite if that makes a difference. This is a very specific use case I am messing with and I realized I am using the GBSC a bit in the "reverse" from the norm.
You could either
-sync combine HV, it will works on devices that will only accept csync like PVMs
or
-mod your GBS to do component (1st page of thread has how-to) and use component out option in web config and use your PVM in component mode (many accept it). Pinout is GBS VGA G/B/R to Y/Pb/Pr.
Also question to rama, can GBS do RGsB (aka sync on green) in addition of component ? Could help some cases where display doesn't have component capacity nor HV input, but does accept RGsB (I think there are some like this ? Not sure honestly) ?
EDIT : yeah some definitively exist, like PVM 1350. Will do RGBS and RGsB only.
Maybe you answered this, but do I have to sync combine HV to get RGBS output or can I pull CSYNC or LUMA Sync while still using RGB instead of compoent. Say a Sony Trinitron that is RGB modded.
rama wrote:
"output at arcade monitor RGB levels"
Not with software alone. Maybe an additional video driver chip could do this? I don't think it'll be easy though.
Tim Worthingtons AV-driver may help here. I've used it for ttl to consumer set levels (and used it to split arcade to gbs, with great results ). I know sync can be set for ttl or 75ohm (in and out). I dont know enough about rgb to know if the gain and attenuation capabilities can get the signal to where @rememberizer wants it.
Guys what's the summary on deprecating VSYNC connectivity? I can't see when the GBS Control firmware stopped needing it and realised maybe it does. The Github Wiki does not ask you to connect VYSYNC to D7, and nor do I see this in user photos. I do however find mention to adding this connection in other places.
Was it deprecated somewhere along the line?
FYI I am writing a brand new GBS-Control guide that aims to get newbies started. I have friends in my local vintage computing group that are buying the hardware but have so many questions so I'm consolidating all my knowledge into a master document and want to ensure it's the best available information. Once I finish the draft (currently 10 pages) I'll link it here and people can just read around the Apple IIGS section
Also I am still getting outstanding picture quality by pressing Gain - then Auto Gain Control toggle. The picture instantly brightens up and looks appropriate (e.g highlights are fine). I wish there was a macro to do this!
NoAffinity wrote:Remember guys, you have to remove the 100 ohm sync->ground resistor when connecting a vga source.
So this has me wondering - and I hope this isn't an annoying question to ask - is this a situation where the RGBS pins and DSUB pins are tied together? And if so, then why exactly do we need the additional termination resistor for sync when using RGBS?
The board is designed to take standard VGA signals, and that's TTL Hsync and Vsync, which are 5v each, right? What's the danger of using an unterminated CSync signal in this situation? I'm not going to use RGBS without the resistor, I'm just wondering why the board can take VGA just fine(?) but somehow unterminated Csync (which I've never seen above 5v) is a problem.
