GBS 8200/8220 CFW Project

The place for all discussion on gaming hardware
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

I just picked up one of these VGA to HDMI converters off of ebay and it works great!

ebay link

The image is slightly less "soft" than those cheapy chinese converters, and most importantly, no rolling noise in the image. I believe it is still limiting the output to limited range, but I am able to increase the brightness on my screen a few extra ticks before black gets a hint of gray in it (compared to the cheapy chinese coverters).

No lag whatsover. I suggest grabbing one at this price while you can if you're in the market.
User avatar
kitty666cats
Posts: 1270
Joined: Tue Nov 05, 2019 2:03 am
Location: Massachusetts, USA

Re: GBS 8200/8220 CFW Project

Post by kitty666cats »

Ryoandr wrote:More like, RGBHV downscaling doesn't work.

RGBS 640x480 (with proper combined sync, 74LS86 circuit) definitively works, tested. (Yes, RGBS over VGA exists, there's an option in some ATI/AMD drivers even)
Component 480p should work.

No idea if simple transistor combiner works.
31kHz RGBS downscaling does work, but it can still be wonky - I have found that 480i RGBS is consistently the least finicky for RGB-specific downscaling. Have not mucked around with YPbPr up/down scaling much though.
User avatar
kitty666cats
Posts: 1270
Joined: Tue Nov 05, 2019 2:03 am
Location: Massachusetts, USA

Re: GBS 8200/8220 CFW Project

Post by kitty666cats »

NoAffinity wrote:I just picked up one of these VGA to HDMI converters off of ebay and it works great!

ebay link

The image is slightly less "soft" than those cheapy chinese converters, and most importantly, no rolling noise in the image. I believe it is still limiting the output to limited range, but I am able to increase the brightness on my screen a few extra ticks before black gets a hint of gray in it (compared to the cheapy chinese coverters).

No lag whatsover. I suggest grabbing one at this price while you can if you're in the market.
I have been eyeing some alternative VGA to HDMIs, myself - I have one of the cheapy 'dongle' shaped ones (DOES have an external PSU, is not actually a 'dongle') and it does the job, yet I always couldn't help but wonder if a slightly nicer one would help. Good to know!
Jon Nielsen
Posts: 37
Joined: Thu May 28, 2020 7:14 am

Re: GBS 8200/8220 CFW Project

Post by Jon Nielsen »

Gunstar wrote:
Jon Nielsen wrote:
Gunstar wrote:@NoAffinity - Same, got an 8220 without the decoupling mod and it's pretty solid. I think rama said it's his favourite model? PS I need to try out your wifi aerial mod!
Did you do anything else to make your 8220 solid? I have a 8220 board that wasn't put to use yet because the 8200 I found was so much better.
Just the recommended mods on the wiki (minus the ones for the charge pump).
Oh OK. I ended up doing that one, but used too large cap for charge pump (same as for C11). Havn't tested if this matters... But it does look as good as the 8200 board now - and might replace it if I find use for the dual output.
immaburr
Posts: 20
Joined: Wed Jun 03, 2020 8:24 pm

Re: GBS 8200/8220 CFW Project

Post by immaburr »

Pardon the noobness but do I have to set anything special to allow input from Component instead of VGA?

Using the Insurrection Industries Scart2DVI - I've tried different settings on the dip switches but I don't believe that made any difference.
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

immaburr wrote:Pardon the noobness but do I have to set anything special to allow input from Component instead of VGA?

Using the Insurrection Industries Scart2DVI - I've tried different settings on the dip switches but I don't believe that made any difference.
On the gbs, no. Just plug in your source and it auto detects.

What dip switches? (something on the scart2dvi I presume...I'm not familiar with them.)

Sent from my SM-G955U using Tapatalk
User avatar
kitty666cats
Posts: 1270
Joined: Tue Nov 05, 2019 2:03 am
Location: Massachusetts, USA

Re: GBS 8200/8220 CFW Project

Post by kitty666cats »

immaburr wrote:Pardon the noobness but do I have to set anything special to allow input from Component instead of VGA?

Using the Insurrection Industries Scart2DVI - I've tried different settings on the dip switches but I don't believe that made any difference.
SCART2DVI’s dip switches are a sync stripper that you can switch on and off, and a low pass filter intended for video capture. Those aren’t going to effect those separate RCA component inputs...

You’re gonna want to be using the SCART2DVI with a DVI to VGA dongle, don’t bother using the output of it on the GBS’s component input jacks - the device outputs a RGBS signal
immaburr
Posts: 20
Joined: Wed Jun 03, 2020 8:24 pm

Re: GBS 8200/8220 CFW Project

Post by immaburr »

SCART2DVI’s dip switches are a sync stripper that you can switch on and off, and a low pass filter intended for video capture. Those aren’t going to effect those separate RCA component inputs...

You’re gonna want to be using the SCART2DVI with a DVI to VGA dongle, don’t bother using the output of it on the GBS’s component input jacks - the device outputs a RGBS signal
Thanks for the clarification!
User avatar
RoboArmy
Posts: 29
Joined: Thu Jul 30, 2020 1:57 am

Re: GBS 8200/8220 CFW Project

Post by RoboArmy »

snip
Last edited by RoboArmy on Tue Sep 29, 2020 5:08 pm, edited 1 time in total.
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

Has anyone tried the sync combiner with gbs control yet - the simple passive circuit that is detailed on retrorgb?

I'm interested to know if it can be integrated in-circuit on the gbs and accept both rgbs sync and rgbhv sync.

I tried doing this with a jrok sync cleaner today. The jrok sc is supposed to accept either sync type and output a clean cmos csync, albeit designed for arcade board input. Im getting a partially stable image with rgbs input and a pretty garbled image with rgbhv. These are inputs from consoles and I'm assuming that the jrok sc isnt designed for this particular application.

Sent from my SM-G955U using Tapatalk
rememberizer
Posts: 37
Joined: Mon Nov 25, 2019 3:38 am

Re: GBS 8200/8220 CFW Project

Post by rememberizer »

NoAffinity wrote:Has anyone tried the sync combiner with gbs control yet - the simple passive circuit that is detailed on retrorgb?

I'm interested to know if it can be integrated in-circuit on the gbs and accept both rgbs sync and rgbhv sync.

I tried doing this with a jrok sync cleaner today. The jrok sc is supposed to accept either sync type and output a clean cmos csync, albeit designed for arcade board input. Im getting a partially stable image with rgbs input and a pretty garbled image with rgbhv. These are inputs from consoles and I'm assuming that the jrok sc isnt designed for this particular application.

Sent from my SM-G955U using Tapatalk
I have used transistor based Sync combiners going into a GBS to combine VGA from Dreamcast / Naomi and downscale it. I also used a second combiner circuit to merge RGBHV into RGBS for the video output. Both systems work great! I tried to find the circuit but I can't! It has a 1k resistor on one line going into the transistor and then a 470ohm on the output pin.


On another note: Is there anything special I have to do to get component output working? I'm using a PS1 SCART RGBS into the GBS. Sync passes through a LM1881 sync stripper with a 470ohm inline resistor. Once I set it to 15khz downscale, I get a good picture with nice colors but bad sync. If I use Passthrough I cant get a picture at all. I assume the component pinout on the DB15 is like this?

Y = Green
Pb = Blue
Pr = Red
Ryoandr
Posts: 269
Joined: Mon Jun 12, 2017 4:12 am

Re: GBS 8200/8220 CFW Project

Post by Ryoandr »

You need an additional mod for component output, it's on 1st post
rememberizer
Posts: 37
Joined: Mon Nov 25, 2019 3:38 am

Re: GBS 8200/8220 CFW Project

Post by rememberizer »

Thank you, I completely missed that!
User avatar
tiochico27
Posts: 18
Joined: Fri Dec 27, 2019 3:03 am

Re: GBS 8200/8220 CFW Project

Post by tiochico27 »

NoAffinity wrote:Has anyone tried the sync combiner with gbs control yet - the simple passive circuit that is detailed on retrorgb?

I'm interested to know if it can be integrated in-circuit on the gbs and accept both rgbs sync and rgbhv sync.

I tried doing this with a jrok sync cleaner today. The jrok sc is supposed to accept either sync type and output a clean cmos csync, albeit designed for arcade board input. Im getting a partially stable image with rgbs input and a pretty garbled image with rgbhv. These are inputs from consoles and I'm assuming that the jrok sc isnt designed for this particular application.

Sent from my SM-G955U using Tapatalk
I'm using a sync combiner with the 74LS86 for my Dreamcast and works fine. That passive circuit from RetroRGB i didn't even try.
User avatar
djc5166
Posts: 101
Joined: Thu Nov 30, 2017 9:50 pm

Re: GBS 8200/8220 CFW Project

Post by djc5166 »

Maybe I missed it somewhere, but are there tagged versions of this firmware? I don't see any tags/releases on github.

Also I see a dev setting for OTA updates, but nothing about using it?

Maybe all this is moot if development is complete, was just curious.
Shiver_169
Posts: 40
Joined: Wed Nov 28, 2018 4:27 pm

Re: GBS 8200/8220 CFW Project

Post by Shiver_169 »

tiochico27 wrote:
NoAffinity wrote:Has anyone tried the sync combiner with gbs control yet - the simple passive circuit that is detailed on retrorgb?

I'm interested to know if it can be integrated in-circuit on the gbs and accept both rgbs sync and rgbhv sync.

I tried doing this with a jrok sync cleaner today. The jrok sc is supposed to accept either sync type and output a clean cmos csync, albeit designed for arcade board input. Im getting a partially stable image with rgbs input and a pretty garbled image with rgbhv. These are inputs from consoles and I'm assuming that the jrok sc isnt designed for this particular application.

Sent from my SM-G955U using Tapatalk
I'm using a sync combiner with the 74LS86 for my Dreamcast and works fine. That passive circuit from RetroRGB i didn't even try.
Hi

Could you share the circuit that you used, a schematic of it would be ideal, I have tried that circuit several times and I have never been able to make it work.
User avatar
kitty666cats
Posts: 1270
Joined: Tue Nov 05, 2019 2:03 am
Location: Massachusetts, USA

Re: GBS 8200/8220 CFW Project

Post by kitty666cats »

I use a Tektronix-branded sync combiner for the output and it works great! I have an inline TTL to 75 ohm BNC cable that I attach to the end. I got it for around $35, but it’s not a bad deal if you search “Tektronix sync combiner” on eBay lol
User avatar
tiochico27
Posts: 18
Joined: Fri Dec 27, 2019 3:03 am

Re: GBS 8200/8220 CFW Project

Post by tiochico27 »

Shiver_169 wrote:
tiochico27 wrote:
NoAffinity wrote:Has anyone tried the sync combiner with gbs control yet - the simple passive circuit that is detailed on retrorgb?

I'm interested to know if it can be integrated in-circuit on the gbs and accept both rgbs sync and rgbhv sync.

I tried doing this with a jrok sync cleaner today. The jrok sc is supposed to accept either sync type and output a clean cmos csync, albeit designed for arcade board input. Im getting a partially stable image with rgbs input and a pretty garbled image with rgbhv. These are inputs from consoles and I'm assuming that the jrok sc isnt designed for this particular application.

Sent from my SM-G955U using Tapatalk
I'm using a sync combiner with the 74LS86 for my Dreamcast and works fine. That passive circuit from RetroRGB i didn't even try.
Hi

Could you share the circuit that you used, a schematic of it would be ideal, I have tried that circuit several times and I have never been able to make it work.
Sure...

https://dcemulation.org/?title=Dreamcas ... ster_Cable
User avatar
djc5166
Posts: 101
Joined: Thu Nov 30, 2017 9:50 pm

Re: GBS 8200/8220 CFW Project

Post by djc5166 »

Trying out the GBS i bought pre-assembled from Chimpnetics on Tindie.

Have a PS2 going into the GBS through his SyncSlayer2 (Great product BTW).

GBS is not outputting anything to my display (Through VGAtoHDMI converter).

I've tried changing various settings with mostly no results. I -DID- get it to work by toggling the RGBHV/Component switch twice in Preferences, which also seems to set the output back to 1280x720. It only works while it's set to this, setting any other output res or setting will break it again.

Setting 720p also does not fix it, only toggling that RGBHV/Component back and forth seems to get it going.

My first thought is I am doing something wrong, but I also see "sync skipped sfr wrong: 0.00" in the debug output. I see earlier in this thread it means you are not wired up correctly for the ext clk, (Debug Pin?) but not sure if this is my issue here?

I’m not sure what the “Debug View” switch is supposed to do, but all it does for me is make the screen brighter. Which also kind of points to the debug pin not connected maybe?
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

Can you post clear pictures of the wiring?

I believe debug view just turns on output via usb to arduino ide's console. Someone correct me if im wrong. It may turn off auto gain so as to not have the auto gain reports print to the console. Or maybe it turns auto gain off? Whenever I turn auto gain on, or off and back in, the image always brightens.

Sent from my SM-G955U using Tapatalk
rama
Posts: 1373
Joined: Wed Mar 08, 2017 3:15 pm

Re: GBS 8200/8220 CFW Project

Post by rama »

Hey,

debug view just makes everything brighter, so that I can check dark areas during development. It doesn't do anything else.
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

rama wrote:Hey,

debug view just makes everything brighter, so that I can check dark areas during development. It doesn't do anything else.
Lol I was waaaaay off.

Sent from my SM-G955U using Tapatalk
immaburr
Posts: 20
Joined: Wed Jun 03, 2020 8:24 pm

Re: GBS 8200/8220 CFW Project

Post by immaburr »

I was thinking about using a VGA to Component cable for Output on my modified GBS8200.

Other than making sure to enable "RGBHW/Component Toggle" do I have to make any additional hardware modifications for this?

If I skipped over this in the project I apologize!
slayrval
Posts: 35
Joined: Wed Oct 07, 2020 6:24 pm

Re: GBS 8200/8220 CFW Project

Post by slayrval »

Hello Everyone! I am new to gbs 8200 and having a great time so far! Thank you rama for the gbs-control software it is pretty great. Only major issue I am having is wifi keeps dropping out and cant reconnect (connected to local wifi). I am guessing it is an interference thing that many others have pointed out. Is there a fix to potentially putting a case around the gbs8200 that is lined with aluminum tape perhaps and mounts the wifi module on the top of case somehow?

A few questions regarding the known hardware mods on the gbs-control github.

1) Remove C11, optionally replace with 22uF (6.3V to 16V) electrolytic cap (Does this apply to the gbscontrol V4.0 black button 2019.10.18 version? If so cap C11 is not through hole so how would you mount an electrolytic capacitor there just solder on top of pads?)
2) Not sure if this was already discuss, but, most of the capacitors on the gbs-control are super cheap 01 cent huahong capacitors and quality seems questionable. Would it be worth replacing all the lytic caps with reputable brands? I am getting wavyness in my image and wondering if maybe its some of these caps causing the issue. I have not yet done the Power supply bypass capacitors fix yet so that may help.
3) With the power supply bypass capacitors mod why cant the old SMD caps be removed completely and replaced with a single higher capacity cap?
Jon Nielsen
Posts: 37
Joined: Thu May 28, 2020 7:14 am

Re: GBS 8200/8220 CFW Project

Post by Jon Nielsen »

immaburr wrote:I was thinking about using a VGA to Component cable for Output on my modified GBS8200.

Other than making sure to enable "RGBHW/Component Toggle" do I have to make any additional hardware modifications for this?

If I skipped over this in the project I apologize!
It depends. I've tested it with a breakout cable and a breakout adapter, probably same type as you're talking about, and it works fine. But the resulting picture is slightly too dark. If that doesn't bother you, it should work.

As I understand it you need to change a resistor to get a value that will allow YPbPr level video. I havn't done this yet because I'm mainly using a 8220 GBS for SCART to dual output VGA -> HDMI + VGA -> OSSC.

Anyway. The front page in fact mentions a mod you can do to correct video level by adding 430 ohm in parallel to the existing R26. I don't know if it'll work with current gbs control implementation, but I'll try this myself eventually on a 8200 and use it for component + VGA -> component :-)
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

If you do the math, a 470R resistor actually gets you as close to 2vp-p as you can get with a standard rating resistor. Somebody check my math or educate me on why a 430R resistor @ >2vp-p would be better than a 470R at 2.0012vp-p (or at least something much closer to almost exactly 2.00000). :)

Sent from my SM-G955U using Tapatalk
User avatar
Gunstar
Posts: 617
Joined: Wed Apr 09, 2014 10:29 am
Location: UK

Re: GBS 8200/8220 CFW Project

Post by Gunstar »

@Rama - Weird request for a future feature but would it be possible to get 480i output from 480p input signal with GBSC?
immaburr
Posts: 20
Joined: Wed Jun 03, 2020 8:24 pm

Re: GBS 8200/8220 CFW Project

Post by immaburr »

It depends. I've tested it with a breakout cable and a breakout adapter, probably same type as you're talking about, and it works fine. But the resulting picture is slightly too dark. If that doesn't bother you, it should work.

As I understand it you need to change a resistor to get a value that will allow YPbPr level video. I havn't done this yet because I'm mainly using a 8220 GBS for SCART to dual output VGA -> HDMI + VGA -> OSSC.

Anyway. The front page in fact mentions a mod you can do to correct video level by adding 430 ohm in parallel to the existing R26. I don't know if it'll work with current gbs control implementation, but I'll try this myself eventually on a 8200 and use it for component + VGA -> component :-)
Thank you for this!
Jon Nielsen
Posts: 37
Joined: Thu May 28, 2020 7:14 am

Re: GBS 8200/8220 CFW Project

Post by Jon Nielsen »

NoAffinity wrote:If you do the math, a 470R resistor actually gets you as close to 2vp-p as you can get with a standard rating resistor. Somebody check my math or educate me on why a 430R resistor @ >2vp-p would be better than a 470R at 2.0012vp-p (or at least something much closer to almost exactly 2.00000). :)

Sent from my SM-G955U using Tapatalk
It would certainly make it easier to test for me. I have plenty of 470R resistors. What calculation are you using ?

Cheers

Jon
User avatar
NoAffinity
Posts: 1019
Joined: Mon May 07, 2018 5:27 pm
Location: Escondido, CA, USA

Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

Jon Nielsen wrote:
NoAffinity wrote:If you do the math, a 470R resistor actually gets you as close to 2vp-p as you can get with a standard rating resistor. Somebody check my math or educate me on why a 430R resistor @ >2vp-p would be better than a 470R at 2.0012vp-p (or at least something much closer to almost exactly 2.00000). :)

Sent from my SM-G955U using Tapatalk
It would certainly make it easier to test for me. I have plenty of 470R resistors. What calculation are you using ?

Cheers

Jon
The calculation on post 1, where Riref = the result of the existing 150r in parallel with x resistor. x = 430r per post 1, and by my calculation 470r is a more precise solution.

Sent from my SM-G955U using Tapatalk
Post Reply