GBS 8200/8220 CFW Project

[Ryoandr]

Hey Rama, remember I told you MVS has sync problems recently ?
Well, turns out it's a specific board that doesn't want to play nice with GBS for some unknown reason. Tried with another, same model MV1FZ, and it runs fine.

That troublesome board also works perfectly with a 15khz CRT monitor.

[ulfrinn]

I was trying to use my board to play Dreamcast over VGA and the image was very, very dark even when the saturation and brightness was maxed, as well as there being a lot of "jailbar" noise in the image. I am waiting until I get a new D1 mini to see how it goes with the control firmware before doing anything else to it. But still unfortunate because over component with the Wii it looked fantastic and I didn't notice any jailbars.

[vol.2]

I was trying to use my board to play Dreamcast over VGA

I'm not sure if the DC VGA solution was ever implemented in GBScontrol. The way I understood it was that DC works ok with 240p/480i, but the 480p implementation of DC is 640x480 centered within a 720x480p image with a DTV pixel clock. I remember reading back on pg. 56 or so that it was not implemented and haven't seen that addressed specifically yet. Ie, it works in 15kHz but not at 31khz.

Be curious to know if this has in fact been ironed out. There are indeed a lot of pages to this thread.

[maxtherabbit]

I was trying to use my board to play Dreamcast over VGA

I'm not sure if the DC VGA solution was ever implemented in GBScontrol. The way I understood it was that DC works ok with 240p/480i, but the 480p implementation of DC is 640x480 centered within a 720x480p image with a DTV pixel clock. I remember reading back on pg. 56 or so that it was not implemented and haven't seen that addressed specifically yet. Ie, it works in 15kHz but not at 31khz.

Be curious to know if this has in fact been ironed out. There are indeed a lot of pages to this thread.

it works, you can use the size and centering controls to get the aspect ratio correct

[NoAffinity]

Yep, works great for DC. And this is a few revisions ago and before clock gen add-on.

https://youtu.be/NsMskwlWTdA

Sent from my SM-G955U using Tapatalk

[flynnsbit]

I tried out the no-solder mod for the GBS-Control for the fun of it. I really don't think it is worth it as the 44 pin socket is snug, but there is a good chance for it to unseat from the chip. I hit it with some hotglue just to keep the PLCC Socket in place. I guess if you had zero soldering experince then it might give you an option. I feel like if you are looking into GBS-Control then you are most likely a tinker-er/Maker and can probably solder 5 pins. I think I will just solder the next one.

Anyway, here are the pics.

[immaburr]

I've been seeing the great things that the gbs-control is able to do with the GBS-8200. I was wondering if this might work in my environment.

I have various systems going into a GScartSW and would like to pass that to the GBS-8200 with gbs-control software to "normalize" the signal and mitigate resolution switching games - Then pass that to the OSSC where it can be further tweaked/doubled/etc.

I've purchased the following for input: https://www.ebay.com/itm/SCART-to-GBS-8 ... 2749.l2649
but would like the output to also be SCART if possible (I guess VGA would work too?) going into the OSSC and then connecting that to an HDMI port on my LCD.

Is this configuration possible with any additional hardware? Are there any recommendations for this? Right now my OSSC is going though my XBOX 1 in order to curb some of the resolution change.

Any help or guidance that can be provided would be greatly appreciated!

[ulfrinn]

I had no issues with the board I ordered off eBay. It's a late 2019 production model, and works well. In fact, now that I got a new D1 mini (set the last one on fire following a bad guide), and got the header pins soldered up on that and connected to the header pins I soldered onto the GBS-8200, the vertical bars I was having before is completely gone. And I turned the potentiometers as far as they'll go which fixed the problem with the image being too dark. End result, Dreamcast and Wii (Gamecube) looks absolutely amazing. I am very pleased with this solution and in light of the issues I had with the pots that I am now convinced are useless, I'll likely desolder those in the near future, and bridge the connection. At the same time, I will probably desolder the white 8-pin RGB header and replace it with ones that will work better with Arduino jumper wires for some experimentation.

I need to get my Sega Genesis running on it next. I will either add a SCART connector and get some Retro Access cables, or make my own cables utilizing a 9-pin connector. Overall though, I am glad I went forward with this project, the GBS-C is definitely worth the effort.

[NoAffinity]

Is this configuration possible with any additional hardware? Are there any recommendations for this?

Gbs to ossc works fine on the ossc vga input. Is there another problem you are trying to solve?

Sent from my SM-G955U using Tapatalk

[immaburr]

Is this configuration possible with any additional hardware? Are there any recommendations for this?

Gbs to ossc works fine on the ossc vga input. Is there another problem you are trying to solve?

Sent from my SM-G955U using Tapatalk

Nope, just wanted to make sure this was a known configuration. Took me a few minutes to realize all I need is a standard VGA cable for output to the OSSC input.

Would I need to connect the 3mm audio jack from the custom scart input board to the OSSC (3mm male to male) to bring over the audio?
https://www.ebay.com/itm/SCART-to-GBS-8 ... 2749.l2649

[NoAffinity]

^yes

Sent from my SM-G955U using Tapatalk

[ulfrinn]

I was wondering if y'all could help me out with something.

So I was doing some experimentation with a Sega Genesis. Managed to stick a couple jumper wires for an arduino into the A/V port on the back of the console and get the A/V port connected to a bread board. I connected sync directly to the GBS-8200, no 470ohm resistor, no 100ohm resistor bridging sync to ground and it looked just fine to me. The other thing I tried was bypassing the capacitors and the resistors to see how well that would go. Bypassing the capacitors seemed to have no ill effect, and bypassing the 75ohm resistors definitely made things brighter, but turning the gain way down in one of the GBS-Control presets seemed to compensate for it.

Is there any reason not to simply jumper my Sega Genesis directly to the GBS-8200's RGB headers, besides the minor inconvenience of having to turn down the gain? And if that's too much of an inconvenience, I could include a 75ohm resistor in-line by trimming the legs, bending them over and jamming them into the female end of a jumper wire and heatshrink over it.

[maxtherabbit]

I was wondering if y'all could help me out with something.

So I was doing some experimentation with a Sega Genesis. Managed to stick a couple jumper wires for an arduino into the A/V port on the back of the console and get the A/V port connected to a bread board. I connected sync directly to the GBS-8200, no 470ohm resistor, no 100ohm resistor bridging sync to ground and it looked just fine to me. The other thing I tried was bypassing the capacitors and the resistors to see how well that would go. Bypassing the capacitors seemed to have no ill effect, and bypassing the 75ohm resistors definitely made things brighter, but turning the gain way down in one of the GBS-Control presets seemed to compensate for it.

Is there any reason not to simply jumper my Sega Genesis directly to the GBS-8200's RGB headers, besides the minor inconvenience of having to turn down the gain? And if that's too much of an inconvenience, I could include a 75ohm resistor in-line by trimming the legs, bending them over and jamming them into the female end of a jumper wire and heatshrink over it.

The sync being connected directly is good, and correct.

Omitting the 75 ohm series resistors on the RGB lines is bad, you're doubling the output voltage that way and clipping your inputs.

DC coupling the video is probably ok

[ulfrinn]

I was wondering if y'all could help me out with something.

So I was doing some experimentation with a Sega Genesis. Managed to stick a couple jumper wires for an arduino into the A/V port on the back of the console and get the A/V port connected to a bread board. I connected sync directly to the GBS-8200, no 470ohm resistor, no 100ohm resistor bridging sync to ground and it looked just fine to me. The other thing I tried was bypassing the capacitors and the resistors to see how well that would go. Bypassing the capacitors seemed to have no ill effect, and bypassing the 75ohm resistors definitely made things brighter, but turning the gain way down in one of the GBS-Control presets seemed to compensate for it.

Is there any reason not to simply jumper my Sega Genesis directly to the GBS-8200's RGB headers, besides the minor inconvenience of having to turn down the gain? And if that's too much of an inconvenience, I could include a 75ohm resistor in-line by trimming the legs, bending them over and jamming them into the female end of a jumper wire and heatshrink over it.

The sync being connected directly is good, and correct.

Omitting the 75 ohm series resistors on the RGB lines is bad, you're doubling the output voltage that way and clipping your inputs.

DC coupling the video is probably ok

What about omitting the caps?

[maxtherabbit]

That's what dc coupling is.

(There are probably 0.1uf caps on the input side of the GBS anyway so it's actually still ac coupled anyway but still)

[ulfrinn]

That's what dc coupling is.

(There are probably 0.1uf caps on the input side of the GBS anyway so it's actually still ac coupled anyway but still)

Alright. So i'll just do what I said above and just bend over the legs on a few 75ohm resistors and just fit them in line of the jumper wires and just use that for connecting my Genesis. The Genesis sits on the top of my desk at most 6 inches from the GBS anyway.

[ulfrinn]

I did what I said. doubled over the legs on a few 75ohm resistors, twisted it up, and put them between a couple female ends on some little jumpers. Hooked it directly into the GBS-8200 and the picture is absolutely gorgeous. However, I am not sure I am getting the correct aspect ratio for the 1280x960 resolution. If anybody knows how exactly I should adjust the scaling on the 1280x960 preset to get the correct aspect ratio, I'd love to know. The proper manual sync settings would be cool too. I get an occasional wavy line on the screen.

[Gollot]

Hello again, i have another question about the hardware "optional" mods, i will be using my GBS with mostly component cables, (OG Xbox, PS2 and Wii with component cables) and a pc with a VGA input, do i need the 75 Ohm / 100 Ohm resistors? (I don't own any consoles with Scart input at the moment) Is there any other mod that i shouldn't need to do?

Thanks for your time.

[maxtherabbit]

Adding the resistor to ground is ONLY for use cases where the GBS is a sink device for a SCART cable or otherwise outputting VIDEO LEVEL SYNC expecting 75-ohm termination

This excludes consoles like the NTSC genesis and SNES, which output TTL level sync when directly connected. It also excludes the YPbPr input, since it follows a completely different signal path to the scaler chip

[rememberizer]

Has anyone used the GBS input side for arcade boards, then passthrough to Component output to a regular tv? Would be really cool if we could use GBS Control as a Component supergun / test bench of some sort. I tried it but the screen is unstable and wobbly using CPS2 and MVS both with resistors between ground/sync and along the sync line. Sometimes the video holds perfectly for a second and then goes off again.

Re: wifi, I can't seem to give different GBS units their own host names. I tried changing all instances of gbscontrol to a specific name in the sketch, but I couldn't pull up the web UI no matter what address I tried on the browser. It works as soon as I flash the default sketch.

[Ryoandr]

Has anyone used the GBS input side for arcade boards, then passthrough to Component output to a regular tv? Would be really cool if we could use GBS Control as a Component supergun / test bench of some sort. I tried it but the screen is unstable and wobbly using CPS2 and MVS both with resistors between ground/sync and along the sync line. Sometimes the video holds perfectly for a second and then goes off again.

There's a page on the wiki about this
https://github.com/ramapcsx2/gbs-contro ... ade-Boards

You should not use GBS directly with JAMMA signals. Potentiometers are not the right way to adjust signals. Use a supergun with some video buffer IC.

[Gollot]

Adding the resistor to ground is ONLY for use cases where the GBS is a sink device for a SCART cable or otherwise outputting VIDEO LEVEL SYNC expecting 75-ohm termination

This excludes consoles like the NTSC genesis and SNES, which output TTL level sync when directly connected. It also excludes the YPbPr input, since it follows a completely different signal path to the scaler chip

Thanks!

A nother question about the mods (I'm a complete noob with electronics)

"Remove C11, optionally replace with 22uF (6.3V to 16V) electrolytic cap" when it mentions (6.3V to 16V) it means that it can be any capacitor between that range?

"Add 10uf / 22uf ceramic SMD capacitors in parallel to stock ones (x4) C23, C41(alternative: C43), C42, C48" or here ( 10uf /22uf ), any of these two should work?

I want to be sure before ordering the components online, thanks for your help.

[rememberizer]

Has anyone used the GBS input side for arcade boards, then passthrough to Component output to a regular tv? Would be really cool if we could use GBS Control as a Component supergun / test bench of some sort. I tried it but the screen is unstable and wobbly using CPS2 and MVS both with resistors between ground/sync and along the sync line. Sometimes the video holds perfectly for a second and then goes off again.

There's a page on the wiki about this
https://github.com/ramapcsx2/gbs-contro ... ade-Boards

You should not use GBS directly with JAMMA signals. Potentiometers are not the right way to adjust signals. Use a supergun with some video buffer IC.

The GBS was made for converting arcade machines, so I would be surprised if they were ever damaged by using arcade signals. I have been using mine for capturing jamma stuff for a while, and I had another for a jamma test bench setup feeding to a VGA monitor. It works fine. I just want to try the component output.

[Ryoandr]

The GBS was made for converting arcade machines

It doesn't mean it is built properly :P

[Gunstar]

I tried out the no-solder mod for the GBS-Control for the fun of it. I really don't think it is worth it as the 44 pin socket is snug, but there is a good chance for it to unseat from the chip. I hit it with some hotglue just to keep the PLCC Socket in place. I guess if you had zero soldering experince then it might give you an option. I feel like if you are looking into GBS-Control then you are most likely a tinker-er/Maker and can probably solder 5 pins. I think I will just solder the next one.

Anyway, here are the pics.

Any more info on this? I can't quite make out how this thing is attached

[flynnsbit]

I took some more pictures:




So basically have this made: https://oshpark.com/shared_projects/KoSLIBGc
Then buy the Wemos D1 and a 44pin socket. And then a 44 pin socket that snaps onto the chip on the GBS 8200. If you remove the little "stubby's" from the underside of the socket it does help with snapping on the socket to the chip on the GBS. FYI. You can see the little stubs in the picture.

44 pin socket can be purchased from here https://www.newark.com/amphenol-icc-fci ... dp/54M6665
or Mouser.

Again, I don't see the benefits over soldering. The socket holding onto the top of the chip is a concern. I had to add hot glue to the socket to hold it.

[Gunstar]

@flynnsbit, thank you for the extra pictures, this makes sense now. I'm guessing someone will be selling these fully assembled/soldered for those with no soldering skills. Very cool!

[flynnsbit]

@flynnsbit, thank you for the extra pictures, this makes sense now. I'm guessing someone will be selling these fully assembled/soldered for those with no soldering skills. Very cool!

Hope so, the design needs some tinkering to make it better for the masses but could open up GBS-Control to users that just can't solder. Hoping someone picks up and sells for others.

What would be even cooler is to include the clock chip in the design so you can just "snap on both in one shot.

[Gunstar]

@flynnsbit, thank you for the extra pictures, this makes sense now. I'm guessing someone will be selling these fully assembled/soldered for those with no soldering skills. Very cool!

Hope so, the design needs some tinkering to make it better for the masses but could open up GBS-Control to users that just can't solder. Hoping someone picks up and sells for others.

What would be even cooler is to include the clock chip in the design so you can just "snap on both in one shot.

An option with the clock board would be even better! it would be nice to recommend this to those on a budget and aren't into tinkering.

Do you know if this is this the solution amoore2600 hinted at a while back?

[flynnsbit]

@flynnsbit, thank you for the extra pictures, this makes sense now. I'm guessing someone will be selling these fully assembled/soldered for those with no soldering skills. Very cool!

Hope so, the design needs some tinkering to make it better for the masses but could open up GBS-Control to users that just can't solder. Hoping someone picks up and sells for others.

What would be even cooler is to include the clock chip in the design so you can just "snap on both in one shot.

An option with the clock board would be even better! it would be nice to recommend this to those on a budget and aren't into tinkering.

Do you know if this is this the solution amoore2600 hinted at a while back?

I'm not positive if this is the exact solution he was referencing, but it seems very likely. I started ordering different sockets to see how close I can get to having a clock snap on. That is going to be a journey. I built the other one for fun and to give me some ideas for different solutions.