GBS 8200/8220 CFW Project

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EmKIronFist
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Re: GBS 8200/8220 CFW Project

Post by EmKIronFist »

NoAffinity wrote:I tried integrating the simple sync combiner circuit talked about on retrorgb, into the vga input, and didnt have any success. Jumbled image, never did get a good synced image, from either rgbs or rgbhv sources.
Had the same issue, but I got better results by removing the resistors on the combined sync output. I ditched the 1k-to-ground resistor as well as the 470 ohm resistor and it worked great when run directly into the GBS' VGA input. The circuit has pretty significant voltage drop vs. the original voltage of either sync line; I realized those two resistors on the C-sync line attenuate it even more, which is totally understandable for the original application but it's overkill for the GBS board, *especially* if you're already using a 100 ohm terminating resistor on the GBS. (I don't even use the 100 ohm terminating resistor, tho, since I don't need it.)

It's amazing if you wanna use something like the Retrotink 2X in passthrough mode! Slap a passive HDMI-to-VGA in there, throw on the sync combiner and you're upscaling S-Video and composite signals easily.

Would not recommend it on signals that are already RGBs though. The resistors + general behavor of the transistor will scramble a C-sync signal. I could see wiring up a DPDT switch in a slightly convoluted way so that one position will run the H-sync pin through the circuit and the other position would run it through a resistor straight into the GBS, though, if you want the adapter to be the last link in the chain before the GBS. That's what I'm gonna be doing eventually, because my current RGB/RGBHV switcher requires a minimum sync voltage of 1.7v and the combiner circuit drops it below that once it's connected, due to the switcher's own terminating resistance.
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kitty666cats
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Re: GBS 8200/8220 CFW Project

Post by kitty666cats »

^

RE: your above post -

Mm, by an Extron interface working better for me than passive circuitry RE: higher Hor. freq/res RGBHV->RGBS *input* (and more in regards to upscaling said signals), looks like we can safely say “get 470ohm resistors the fuck outta dere/feed it big fat powarful sync voltage” xD

...or YPbPr haha

And yeah, for OUTPUT most any passive combining circuitry should be plenty cooperative (except livin’ dangerously and immediately trying BNC T adapters with single every output dislay/device) - come to think it, the circuit on RetroRGB is probably far better suited for the output connector of GBSC, which I suppose would apply to *downscaling* in most use cases.
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maxtherabbit
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Re: GBS 8200/8220 CFW Project

Post by maxtherabbit »

has anyone ever tried using the GBS-C in passthrough mode as a colourspace transcoder and using a light gun with it?

it has been tested to be zero lag in this mode so it *should* work but wondering if anyone has confirmed it?
fernan1234
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Re: GBS 8200/8220 CFW Project

Post by fernan1234 »

maxtherabbit wrote:has anyone ever tried using the GBS-C in passthrough mode as a colourspace transcoder and using a light gun with it?

it has been tested to be zero lag in this mode so it *should* work but wondering if anyone has confirmed it?
Pretty sure it should work for 240p inputs. I tested 480i and it doesn't work, so won't be good for Dreamcast, PS2, etc. light gun games.
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orange808
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Re: GBS 8200/8220 CFW Project

Post by orange808 »

All Gonbes internal processing will happen in 4:2:2 YpPbPr color space component. This is unavoidable.

So, it be more comfortable and convenient to use something like RGB2COMP before the Gonbes and feeding everything that way. Less than absolutely optimal sampling from the RGB2COMP doesn't matter, because the GBS doesn't do optimal sampling. The color space conversion of the RGB2COMP will be as good or better than the GBS (and the GBS always does this step itself with RGB).

Converting all your RGB to component won't matter, because it always happens anyway.
We apologise for the inconvenience
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maxtherabbit
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Re: GBS 8200/8220 CFW Project

Post by maxtherabbit »

fernan1234 wrote:
maxtherabbit wrote:has anyone ever tried using the GBS-C in passthrough mode as a colourspace transcoder and using a light gun with it?

it has been tested to be zero lag in this mode so it *should* work but wondering if anyone has confirmed it?
Pretty sure it should work for 240p inputs. I tested 480i and it doesn't work, so won't be good for Dreamcast, PS2, etc. light gun games.
Good to know, I was going to use it for PS2 so I guess that's out. Thanks
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maxtherabbit
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Re: GBS 8200/8220 CFW Project

Post by maxtherabbit »

It's been discussed at length how the mode detection of the GBS-C does not appreciate RGBHV sources. My question is whether the presence of V-sync is relevant if you are sending C-sync to pin 13?

I.e. would C-sync on pin 13 and V-sync on pin 14 still enjoy the superior mode detect logic, or would it act like an RGBHV source?
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Syntax
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Re: GBS 8200/8220 CFW Project

Post by Syntax »

If GBS detects V sync at all it will bypass.
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maxtherabbit
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Re: GBS 8200/8220 CFW Project

Post by maxtherabbit »

Syntax wrote:If GBS detects V sync at all it will bypass.
I'm not sure what you mean by "bypass"? I know it is capable of scaling RGBHV sources with varying degrees of success
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Syntax
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Re: GBS 8200/8220 CFW Project

Post by Syntax »

Things must of changed then. Vsync was always the switch for bypassing the scaler.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

@OverlordManny just sent me a text with pics of the finished case, looks great!

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TABYDACAT
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Re: GBS 8200/8220 CFW Project

Post by TABYDACAT »

TABYDACAT wrote:
AndehX wrote:
TABYDACAT wrote:I saw earlier in this thread that someone thought it would be nice to have physical buttons to select/load their custom presets. As a side thing I wanted to work on, I decided to give it a try. This edit is kinda messy, but through testing, I haven't noticed hiccups to the actual use of the device during gameplay. OLEDs can now be used to display which preset is being selected/loaded, boot-up messages, and various GBS data (resolution, input, etc.).

No idea if this would actually be useful, but if this sounds like something interesting, I can send around the edit. I already have a to-do list for this, but perhaps some others have good feedback for the functionality or aesthetics. The hardware needed to actually use this is straightforward, consisting of three components: SSD1306 128x64 I2C OLED and two toggle push buttons.

Some other things to note:
- SCART, VGA and Component were used to test (PS1,Dreamcast and PS2)
- I opted to use this particular OLED due to size, cost and availability. Could change in the future to use LCD screens or perhaps both that way users have an option on what they want to use.
- Different configs of this OLED don't matter, like color. Just make sure the size and comm. method is the same
- I'm still working on this so expect weird or unusual things, particularly the OLED functionality.

When taking this photo no input was connected hence the bypass and interesting refresh rate, after some time it will blink "No Signal"
Here's a some example photos:
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EDIT: I've now completed this edit to a usable state and soldered to a protoboard in the mean-time. There is some minor issues software-wise, but that will fix be shortly. Here's some crappy pictures to illustrate an example of a GBS 8200 with an OLED. Using a PS1 via SCART. I forgot to picture this, but you can might able to see the two buttons that control the loading/selecting of the presets.
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Do you have any updates on this? a guide to build it etc? I would love to make something like that.
I'm terribly sorry for the long duration between replies for this. I have made a quick guide to get this up and running (there's probably typos lol). Even though its pretty simple to get everything connected, I wanted the guide to be somewhat detailed. If there's anything that needs to be addressed and that isn't in the guide already, please let me know. Can't wait to see this running in others setups!

Guide:
Spoiler
For those interested, I'm currently working on transferring and trimming this code to the new release of GBS-C. I've also been working on converting new fonts for the OLED to closely match the style of the new UI. Thanks for reading and hopefully some users can have some fun with customizing their GBS further. The link should still work in case anyone wants to test out that release beta which still has the original UI.
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SCARTicus
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Re: GBS 8200/8220 CFW Project

Post by SCARTicus »

TABYDACAT wrote: For those interested, I'm currently working on transferring and trimming this code to the new release of GBS-C. I've also been working on converting new fonts for the OLED to closely match the style of the new UI. Thanks for reading and hopefully some users can have some fun with customizing their GBS further. The link should still work in case anyone wants to test out that release beta which still has the original UI.
This was needed. Thank you. I hate having to use my damn phone just to operate a scaler. That was always a ridiculous proposition. Now with the case we're finally starting to see a complete product rather than a permanent project. Maybe I'll finally get my GBS-C out of its shoebox enclosure.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

Looks nice. FYI the OLED can be gotten on eBay for $5.49 USD shipped, tactile buttons for about the same. The case I just had printed will have to be modified to accept the LCD, but this looks like a better option than the wifi interface, and even though I think the wifi is very cool, its still a bit of a hassle.
lucaslbds
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Re: GBS 8200/8220 CFW Project

Post by lucaslbds »

Hello, guys. has anyone noticed while playing, some game flashes, like lightning, and the gbs flashes the light of the WiFi module and the screen is weird for 1 second? as if gbs control didn't know how to deal with these flashes.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

Havent had the above problem, but admittedly havent spent a lot of time using the unit yet.

Just finished installing in my case, looks great. I had to grind a bit off of the spacers on the bottom plate as they were a bit too thick, but otherwise fits like a glove. Very sturdy too. I havent installed a SCART connector yet, and Ive yet to figure out whats the best VGA > HDMI adapter to use as far as that goes, but otherwise smooth sailing.
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Kez
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Re: GBS 8200/8220 CFW Project

Post by Kez »

lucaslbds wrote:Hello, guys. has anyone noticed while playing, some game flashes, like lightning, and the gbs flashes the light of the WiFi module and the screen is weird for 1 second? as if gbs control didn't know how to deal with these flashes.
When your screen is suddenly fully white, that's like all of the signals turned up to max.. so perhaps they are going too high. Is this happening on multiple systems or just one? What AV cable are you using? Which mods have you done to the GBS?
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Gunstar
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Re: GBS 8200/8220 CFW Project

Post by Gunstar »

Josh128 wrote:Havent had the above problem, but admittedly havent spent a lot of time using the unit yet.

Just finished installing in my case, looks great. I had to grind a bit off of the spacers on the bottom plate as they were a bit too thick, but otherwise fits like a glove. Very sturdy too. I havent installed a SCART connector yet, and Ive yet to figure out whats the best VGA > HDMI adapter to use as far as that goes, but otherwise smooth sailing.
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The case looks great, Josh, liking the two-tone especially
lucaslbds
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Re: GBS 8200/8220 CFW Project

Post by lucaslbds »

Kez wrote:
lucaslbds wrote:Hello, guys. has anyone noticed while playing, some game flashes, like lightning, and the gbs flashes the light of the WiFi module and the screen is weird for 1 second? as if gbs control didn't know how to deal with these flashes.
When your screen is suddenly fully white, that's like all of the signals turned up to max.. so perhaps they are going too high. Is this happening on multiple systems or just one? What AV cable are you using? Which mods have you done to the GBS?
so far the Mega Drive was what I noticed the most, because it has many games that have these flashes, like Sonic 3, Street Fighter 2 (when you press start on the continue screen, you know?). the Mega Drive is equipped with a rgb device that transcodes into component video, then it goes to GBS. about her modification, here in Brazil there is a guy who assembles the gbs on a circuit that he does himself, that has scart inputs and also has a Wi-Fi module. the guy’s name is Fábio Michelin from GamesCare, he buys raw gbs, modifies and sells to us.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

Gunstar wrote: The case looks great, Josh, liking the two-tone especially
Thanks man, I dig the two tone also. I chose that based off the original Jeff Chen case. Jeff Chen, BTW, did a bang up job designing the original, hats off to him.
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NoAffinity
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Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

lucaslbds wrote:
Kez wrote:
lucaslbds wrote:Hello, guys. has anyone noticed while playing, some game flashes, like lightning, and the gbs flashes the light of the WiFi module and the screen is weird for 1 second? as if gbs control didn't know how to deal with these flashes.
When your screen is suddenly fully white, that's like all of the signals turned up to max.. so perhaps they are going too high. Is this happening on multiple systems or just one? What AV cable are you using? Which mods have you done to the GBS?
so far the Mega Drive was what I noticed the most, because it has many games that have these flashes, like Sonic 3, Street Fighter 2 (when you press start on the continue screen, you know?). the Mega Drive is equipped with a rgb device that transcodes into component video, then it goes to GBS. about her modification, here in Brazil there is a guy who assembles the gbs on a circuit that he does himself, that has scart inputs and also has a Wi-Fi module. the guy’s name is Fábio Michelin from GamesCare, he buys raw gbs, modifies and sells to us.
Make sure it is flashed to the most recent firmware. This sounds like an issue that was resolved many firmware ago.

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AndehX
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Re: GBS 8200/8220 CFW Project

Post by AndehX »

Josh128 wrote:Havent had the above problem, but admittedly havent spent a lot of time using the unit yet.

Just finished installing in my case, looks great. I had to grind a bit off of the spacers on the bottom plate as they were a bit too thick, but otherwise fits like a glove. Very sturdy too. I havent installed a SCART connector yet, and Ive yet to figure out whats the best VGA > HDMI adapter to use as far as that goes, but otherwise smooth sailing.
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Man it's such a shame there isn't a version of this case for the 8220
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

^^
I would think it would be super easy to modify the design to replace the HDMI connector with another DE-15.

I just installed a female SCART RGBS input into the case. For this case, I had to grind the mounting ears off the connector and also take a bit of material off of the sides of the connector to get it to fit. Having no proper way after that to secure it, I had to hot glue it in place.

Not exactly sure of the impedance requirements, I did a straight wire job from each SCART pin to the RGBS+ground CGA pins on the 8200. It seems to work without issue so far using the Genesis model 2 Im currently testing with. Compared to the SCART > YUV Converter > GBS 8200 component in chain I used earlier, I cant really say I see any greater clarity, brightness, or sharpness (it was already pretty damned great), but now I am 100% sure that my colors are accurate vs using the YUV converter, which can drift and is adjustable, and I have the added benefit of a simplified signal chain which is a big plus in my book.

Using this case, I was able to relocate the Arduino board farther away from the scaler IC, and it seems to have definitely improved the WiFi dropouts I experienced earlier. I havent done much extensive testing in that regard but it didnt drop out at all that I could see in the 20 minutes I played around with it yesterday after I installed the SCART connection.

Below are some cell phone pics of the finished unit running with SCART and also a couple of pics of the monitor. I was just testing here and havent installed the heat shrink over the RGBS wires on the SCART yet. I think I will also add a 1/8" stereo audio jack on the side of the case closest to the SCART connector and connect to the audio pins on the SCART so that no special breakout cable will be needed for audio. That and still looking into the HDMI out options. Will update as things progress.
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Last edited by Josh128 on Fri Mar 19, 2021 1:40 pm, edited 1 time in total.
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NoAffinity
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Re: GBS 8200/8220 CFW Project

Post by NoAffinity »

^looks great! P12 is probably you bet bet for getting the VGA out to some form of hdmi out (but you may have already known that). aliexpress sells the wired p12 connectors for very cheap - micro jst mini 2.0.

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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

^

Yeah, P12 is what I was thinking. Finding a ready made connector to DE-15 would definitely simplify things, I will look into that, thanks!
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BMF54123
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Re: GBS 8200/8220 CFW Project

Post by BMF54123 »

Does anyone get horizontal smearing when RGB sources are connected? I bought a female SCART plug and wired it up to the RGBS input on my GBS 8200, and at least on the PS2, there's a definite "shadow" to the right of sharp brightness transitions that isn't there on YPbPr, or when I use my OSSC:

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I added a 100 ohm resistor between sync and ground as specified in the recommended hardware mods, but everything else (aside from the NodeMCU) is stock. The SCART cable is a dedicated PS2 cable with no capacitors on the RGB lines. Is this just a normal thing with the GBS 8200? It isn't a huge deal, since I can just use the YPbPr inputs with the PS2, but I'd like to maybe use this with other 480i RGB devices in the future, since the OSSC doesn't have the nice motion-adaptive deinterlacing.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

Looking closely at the pictures, the ONLY one without issue is the component. The OSSC shots have "drop shadows" above and below the bottom of blacks. Look closely at the first line.

What are you capturing the output of the GBS with? Are you coming out VGA or HDMI and if HDMI, what kind of vga to hdmi ADC are you using?
Kaixe Rho
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Re: GBS 8200/8220 CFW Project

Post by Kaixe Rho »

I built this months ago now and have so many questions and concerns I keep delaying posting here about it.
Here is my most burning question, moreso than the image and colors being ruined on passthrough, moreso than questions about mods necessary to use component output with full quality retention:

Instead of 640×480, the only 480p option is 720×. I have seen it numerous times being brought up before, but I have to ask: what is the intended use case here? I have a crt monitor, and modded the 8200 because it was showcased in a retrorgb video about them, and mostly love my results - but the addition of dead space on the left and right sides of the image means that nothing fits correctly on my VGA monitor. There are of course the picture control options on the second page, but when I try to increase the horizontal size to fill in the dead space, getting close to it causes the image to dissolve into static the closer I get to filling it.

I assume I might just under some false assumptions, or maybe my board is damaged, so If this sounds off, let me know.
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Josh128
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Re: GBS 8200/8220 CFW Project

Post by Josh128 »

Just set your monitors horizontal width control to its max, then use the GBS to increase width till it covers the screen. I can do it with no issues on the 17" VGA monitor Im testing on. Are you saying its not working for you?
fernan1234
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Re: GBS 8200/8220 CFW Project

Post by fernan1234 »

Kaixe Rho wrote:Instead of 640×480, the only 480p option is 720×.
720x480 is 480p, i.e. the EDTV standard. 640x480 is a VESA/Computer display standard. Use cases for 480p include EDTV-compatible TVs/displays, as well as video processors and modern TVs whose scaling algorithm expects EDTV signals but not necessarily all or any VESA/PC resolutions. On a PC CRT, I imagine that it would be easier to adjust horizontal and vertical sizing. If your VGA monitor is a fixed-pixel display, what is its native resolution?
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