GBS 8200/8220 CFW Project

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Stremon
Posts: 20
Joined: Wed May 23, 2018 11:27 am

Re: GBS 8200/8220 CFW Project

Post by Stremon »

keremimo wrote:Stremon: Just to understand how your switch works, do you get an image when you set the stock firmware on RGBHV mode? That one is not completely implemented yet.

Also, looking at your NodeMCU, it seems that you have not powered it yet? It needs power as well. Connect it to USB or use VIN input & a ground with 5v.
Indeed it's in RGBHV that I get an image. But shouldn't it at least be something coming out of the VGA out, even if the input isn't recognized?
I mean when I switch the stock GBS on, even without input I go a video out signal. With GBS control I got no video signal at all, whatever profile I try loading.

For the NodeMCU, I saw in the tutorial it could be powered in 3.3V by the GBS VCC and GND, which I did (the red and black cable in my picture), but maybe I didn't plug into the correct pins?
The NodeMCU powers on fine and I can access the web interface.
I tried with a powered USB cable as you suggested, but it doesn't change a thing.
keremimo
Posts: 46
Joined: Fri Apr 27, 2018 12:16 pm

Re: GBS 8200/8220 CFW Project

Post by keremimo »

Stremon wrote:
keremimo wrote:Stremon: Just to understand how your switch works, do you get an image when you set the stock firmware on RGBHV mode? That one is not completely implemented yet.

Also, looking at your NodeMCU, it seems that you have not powered it yet? It needs power as well. Connect it to USB or use VIN input & a ground with 5v.
Indeed it's in RGBHV that I get an image. But shouldn't it at least be something coming out of the VGA out, even if the input isn't recognized?
I mean when I switch the stock GBS on, even without input I go a video out signal. With GBS control I got no video signal at all, whatever profile I try loading.

For the NodeMCU, I saw in the tutorial it could be powered in 3.3V by the GBS VCC and GND, which I did (the red and black cable in my picture), but maybe I didn't plug into the correct pins?
The NodeMCU powers on fine and I can access the web interface.
I tried with a powered USB cable as you suggested, but it doesn't change a thing.
The RGBHV is just passthrough at the moment, and that is only with the development branch. Rama mentions this a few posts above. You just have to wait or find another way to connect your SCART to the GBS board :)
Stremon
Posts: 20
Joined: Wed May 23, 2018 11:27 am

Re: GBS 8200/8220 CFW Project

Post by Stremon »

keremimo wrote: The RGBHV is just passthrough at the moment, and that is only with the development branch. Rama mentions this a few posts above. You just have to wait or find another way to connect your SCART to the GBS board :)
Thank you for the info, I think I will try getting a D Terminal to YUV cable (it the same YUV signal) to plug into the GBS input instead of the VGA :)
But it still doesn't explain why I get no signal at all out of the GBS, like it's not powered at all... :/
rama
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Joined: Wed Mar 08, 2017 3:15 pm

Re: GBS 8200/8220 CFW Project

Post by rama »

Hey,

I'm not quite sure what your source is. You probably use different sources, and it won't work on any of them, right?

For RGBHV into the GBS:
Support for this is brand new. You'll need to flash the development branch for this to have a chance of working.

SD sources (240p) via RGBS:
This is where you need that 100 Ohm resistor between the "S" and "GND" pins on the 5 pin RGBS input header.
The resistor completes the expected input termination for AV systems that most consoles of the time where built for.
From here on, I expect maybe 90% of sources to get recognized and the system producing a picture.
Results will be best if the source is already properly sync stripper processed.
(By the way, the GBS will not produce any output without a valid preset loaded. H+V sync will be low and no data on the 3 video lines either.
What you get with stock firmware is from extra circuitry outside the scaler chip, driven by the original MCU, which has an OSD generator built in.)

With this extra information, maybe you can fix your issue now.
If not, we'll help :)

Most televisions probably won't support those 70-75hz modes so I guess next in line is to grab those frames and put them through a 60hz preset, right?
Well, nope.
Passing on unmodified signals is very much easier than actually recognizing and reprocessing them.
The new bypass mode is probably the most barebones way of getting the chip to digitize incoming video and then DAC it to be output again.
I don't know yet what the chip can do from this point on.
It'd be great if it could do some light processing, maybe even a pure linedouble and output option..
We'll see :)
keremimo
Posts: 46
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Re: GBS 8200/8220 CFW Project

Post by keremimo »

Well, nope.
Passing on unmodified signals is very much easier than actually recognizing and reprocessing them.
The new bypass mode is probably the most barebones way of getting the chip to digitize incoming video and then DAC it to be output again.
I don't know yet what the chip can do from this point on.
It'd be great if it could do some light processing, maybe even a pure linedouble and output option..
We'll see :)
Ah, darn. It would be able to do what OSSC couldn't :)

How difficult would linedouble be anyways?

Also, a question! Can we get pure interlaced output resolutions instead of progressive for 480i inputs? I think that could work way better since TV's and capture devices have some sweet de-interlace options that look cleaner. Kinda like OSSC's interlaced passthrough? Could be optional or something like that, maybe?
Stremon
Posts: 20
Joined: Wed May 23, 2018 11:27 am

Re: GBS 8200/8220 CFW Project

Post by Stremon »

rama wrote:Hey,

I'm not quite sure what your source is. You probably use different sources, and it won't work on any of them, right?

For RGBHV into the GBS:
Support for this is brand new. You'll need to flash the development branch for this to have a chance of working.

SD sources (240p) via RGBS:
This is where you need that 100 Ohm resistor between the "S" and "GND" pins on the 5 pin RGBS input header.
The resistor completes the expected input termination for AV systems that most consoles of the time where built for.
From here on, I expect maybe 90% of sources to get recognized and the system producing a picture.
Results will be best if the source is already properly sync stripper processed.
(By the way, the GBS will not produce any output without a valid preset loaded. H+V sync will be low and no data on the 3 video lines either.
What you get with stock firmware is from extra circuitry outside the scaler chip, driven by the original MCU, which has an OSD generator built in.)
Again thank you for the info, it's very useful :)
So far I can only imput RGBHV, but planning to try YPbPr (is that actually supported?)

So I guess I can find the dev version in one of the GitHub branches, right?

Will try it out and see if it works ;)
rama
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Joined: Wed Mar 08, 2017 3:15 pm

Re: GBS 8200/8220 CFW Project

Post by rama »

Interlaced output is possible but I never tested this. It would still be retimed due to other constraints, so it won't look good even on the best deinterlacers.

@Stremon: https://github.com/ramapcsx2/gbs-contro ... evelopment
silensilen
Posts: 2
Joined: Thu Jun 21, 2018 6:59 am

Re: GBS 8200/8220 CFW Project

Post by silensilen »

Hello!
First of all I wanted to thank you for your work.
I use your code to connect to the GBS-8200 Soviet retro computer BK0010-01 via RGBS
Everything works well. But the monitor of the LG 1530s does not support the output frequency, it reports the output from the range.
The parameters of this monitor are: lines: 31-63 kHz; frames: 56-75 Hz
Is it possible to correct the code, what would this monitor have earned?
Thank you in advance for your answer.
keremimo
Posts: 46
Joined: Fri Apr 27, 2018 12:16 pm

Re: GBS 8200/8220 CFW Project

Post by keremimo »

rama wrote:Interlaced output is possible but I never tested this. It would still be retimed due to other constraints, so it won't look good even on the best deinterlacers.
Would it look better than what we currently have for interlaced sources though? Like, worth a shot?
silensilen
Posts: 2
Joined: Thu Jun 21, 2018 6:59 am

Re: GBS 8200/8220 CFW Project

Post by silensilen »

Hello!
First of all I wanted to thank you for your work.
I use your code to connect to the GBS-8200 Soviet retro computer BK0010-01 via RGBS
Everything works well. But the monitor of the LG 1530s does not support the output frequency, it reports the output from the range.
The parameters of this monitor are: lines: 31-63 kHz; frames: 56-75 Hz
Is it possible to correct the code, what would this monitor have earned?
Thank you in advance for your answer.
keremimo
Posts: 46
Joined: Fri Apr 27, 2018 12:16 pm

Re: GBS 8200/8220 CFW Project

Post by keremimo »

silensilen wrote:Hello!
First of all I wanted to thank you for your work.
I use your code to connect to the GBS-8200 Soviet retro computer BK0010-01 via RGBS
Everything works well. But the monitor of the LG 1530s does not support the output frequency, it reports the output from the range.
The parameters of this monitor are: lines: 31-63 kHz; frames: 56-75 Hz
Is it possible to correct the code, what would this monitor have earned?
Thank you in advance for your answer.
It seems that your monitor doesn't support 50hz frequencies and that seems to be the problem. I bet that Soviet computer outputs a PAL signal. gbs-control does not do signal conversion to 60hz for compatibility yet :(
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Yeah, I forgot that home computers mostly used PAL / NTSC variants to allow plugging into regular TVs.
There are 2 options:
- get a more modern monitor
- hack 50Hz to 60Hz conversion into gbs-control

I largely favor option 1, simply because frame rate conversion would look horrible and clutter my nice and tidy code even more ;p
Any TFT I ever tested supported 50Hz. I usually go for models made around 2007 or later.

Regarding interlacing:
I haven't looked into it but there's a flag to set which "enables" the feature in VDS. Of course this won't be enough and I'll have to find out what else it requires, as usually.
Maybe some day. I'd like to focus on other features first.

@Stremon:
Forgot to mention that but yeah, YPbPr over the RCA jacks is well supported. Anything from 240p/480i up to 720p will be of good quality.
1080i / 1080p is iffy but at least you'll get a picture from 1080i.
The limitation is just in my software. I haven't had the time yet for better HD support.
The chip supports it just fine and might even get higher ;)
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Just a heads up everyone:

Custom presets are only valid for the version of gbs-control they were created with.
If you update gbs-control, remember to select "Erase Flash > All Flash Contents" once, which will clean the flash.

Old presets will continue to be loaded and probably work fine but things may go weird at some point.
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orange808
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Re: GBS 8200/8220 CFW Project

Post by orange808 »

Does this have frame lock?
We apologise for the inconvenience
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Depends on the mode / input.
It's fully locked in RGBHV (using the source sync directly).
In RGBS or Component Video mode, there's an optional frame time lock mode (the MCU will regulate timings for a "soft" frame lock).
It doesn't work on all displays though.
Higgy
Posts: 54
Joined: Thu Mar 15, 2018 1:29 pm

Re: GBS 8200/8220 CFW Project

Post by Higgy »

I took along my 8220 and your CFW to show off at an AMIGA meet we had, people liked your work :)

Question - is there a way to input composite or S-video? I have a few composite (NES, MSX computer) systems and S-Video (C64 & N64) systems.
redcatex
Posts: 35
Joined: Sat Jun 09, 2018 4:34 pm

Re: GBS 8200/8220 CFW Project

Post by redcatex »

First of all Hi all, and big thanks for you guys who created this awesome project. Thanks Rama for all hard work you putting in.

Now straight to the point i have build hardware, it's been nicier, but because of faulty playstation rgb chinese cable i thought i did something wrong with sync seperator, but it's not about it. Now I have fully working setup.

I have one question regarding scanlines, software scanlines aren't uniform for me somehow sometimes it's not very evenly spaced more like
-
-
_
_
-
-
-

Something like this, few are closer to other. Sorry for no screenshot, question is, is it still profitable to create hardware slg ? will it be better ?
I have tested on PAL n64 (rgb moded [installed rgb pcb]). and pal gamecube.
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Higgy, that's awesome! Hope your board didn't show that slight noise issue though :p
https://github.com/ramapcsx2/gbs-contro ... l-gbs-8220

redcatex,
Uneven scanlines is a typical issue with non-integer scaling.
I'd say it's even expected with the default settings. The scanline feature is just a fortunate glitch anyway ;p

You can optimize it by increasing or decreasing the number of lines to some factor that works with the other parameters.
Involved are the source, the vertical scaling factor and the output number of lines.
I had good results with the default 1280x960 preset at 1024 visible lines.
It's tricky to get there, but try sending these commands over terminal:
wvt 1067
.

(Yes, just a dot is command #2)
This will set 1067 total lines, for 1024 visible, then correct htotal for the new timings.
If you get a picture now, you probably need to scale it a little (use the web ui).
Scanlines should be even now.

If I had more space, I would offer this as a preset..
Rodrik
Posts: 18
Joined: Tue Jul 03, 2018 12:28 pm

Re: GBS 8200/8220 CFW Project

Post by Rodrik »

rama wrote:Higgy, that's awesome! Hope your board didn't show that slight noise issue though :p
https://github.com/ramapcsx2/gbs-contro ... l-gbs-8220
Hi Rama

I just have the same exact model as the one you posted on github on this link and I have this noise issue, but I did not understand what must be done apart removing c11, what do you mean about R58 with "bead" and where would you add extra smd capacitors?

Many thanks for all your work around this GBS.

Rodrik
Higgy
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Re: GBS 8200/8220 CFW Project

Post by Higgy »

rama - don't worry, I've had my 8220 for quite a while, so I have done most of the 'fixes' over the years. Cap replacement, grounded copper tape added, board dipped in holy water & blood sacrifice.

I still have C11 from memory, but I also now power my board off a 5V phone charger.

I can't remember when the 'white speckles' went and with which mod, but I am glad they have gone!
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

The speckles are from the ofw driving a pretty high memory clock with no subtiming adjustments.
Originally, the issue is that there are no dampening resistors on any of the memory traces.
With that kind of setup, you can't just push 162Mhz signals around. But the ofw does ;p

The quick fix is adding shielding. It probably works by coupling the fast edges onto other traces and ground, and also delaying the signals a little.

The other fix is to just run the memory slower, which is what I do.
Most presets work fine with just 81Mhz (the lowest it can do), so I don't even know why they wanted that high clock in the first place.

Here's an image of what I believe is Tvia's demo / reference board. Notice the resistors (22Ohm, I think). Oh, and no heatsink!
Image

Anyway, there's still that curious Intersil video buffer that can provide negative voltage signals.
It's an odd choice for these boards. I guess it can be useful to have a line driver if you want 2 outputs, but why use a special IC like the Intersil?
The boards were never meant to output Component Video. Maybe they considered it but then dropped the option, but the video amp stayed.
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Currently doing a test run of a GBS yellow button board with the heatsink removed.
The chip gets hot but seems to top out at a level where it's just a bit too much to touch.
It's running fine so far.

The reason for the test:
Heasinks act as antenna for the switching noise / EMI. Removing it helps with the ESP8266 WiFi dropping out at certain PLLAD frequencies.
Also, it should reduce noise on the analog sections. (There'll be increased thermal noise but much less switching noise)

If anyone else wants to try, I think it's fine.
Make sure to only use my software though. The ofw burns 30% more power ;p
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AndehX
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Re: GBS 8200/8220 CFW Project

Post by AndehX »

rama wrote:Currently doing a test run of a GBS yellow button board with the heatsink removed.
The chip gets hot but seems to top out at a level where it's just a bit too much to touch.
It's running fine so far.

The reason for the test:
Heasinks act as antenna for the switching noise / EMI. Removing it helps with the ESP8266 WiFi dropping out at certain PLLAD frequencies.
Also, it should reduce noise on the analog sections. (There'll be increased thermal noise but much less switching noise)
Wouldn't a better solution be to use a ceramic heatsink?

https://www.ebay.co.uk/itm/HEAT-SINK-30 ... Sw-K9ZJIlG
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Yep, that would be best.
It's quite the act to remove the heatsink by the way. I used a heat gun and 2 thin screwdrivers.
Definitely not a casual mod :p
TobiasRieper
Posts: 57
Joined: Thu Sep 28, 2017 8:04 pm

Re: GBS 8200/8220 CFW Project

Post by TobiasRieper »

I used to get noise especially on pal signals but I used the copper tape method and it's completely vanished. I haven't needed to replace any caps on my GBS board. Word of warning, I was silly enough to epoxy the WiMos board on top of the GBS heatskink. It got so hot that it melted some of the solder joining some of the legs on the chip. I've now filed down the plastic on the yellow. component inputs and epoxied the WiMos board to that. Works fine.
rama
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Joined: Wed Mar 08, 2017 3:15 pm

Re: GBS 8200/8220 CFW Project

Post by rama »

Rodrik wrote:
rama wrote:Higgy, that's awesome! Hope your board didn't show that slight noise issue though :p
https://github.com/ramapcsx2/gbs-contro ... l-gbs-8220
Hi Rama

I just have the same exact model as the one you posted on github on this link and I have this noise issue, but I did not understand what must be done apart removing c11, what do you mean about R58 with "bead" and where would you add extra smd capacitors?

Many thanks for all your work around this GBS.

Rodrik
Hey,

near the VGA out ports you can find a tiny 16 pin IC (ISL59833).
The IC is an interesting video driver for this board. It generates a negative voltage internally that goes unused for all I can tell.
But this feature requires it operating a charge pump, which generates noise. This noise is what shows up in the final picture.

Just below the ISL59833 are resistors R58 and R59, both with a "0" marking.
They are zero Ohm resistors, basically a direct connection. The engineers made it this way to later be able to use filters in those locations.
R58 is the location for the charge pump power supply filter.
A ferrite bead at this location will isolate the generated noise from the rest of the circuit.
To be effective, a small bypass capacitor should also be installed, but there is no pad for it.

So that's the idea:
Desolder R58 and replace it with a ferrite bead, add a ~220nF SMD capacitor to ground (between left side of R58 and right side of R59 will work).
Intersil recommends a "Panasonic 120Ω Bead EXC3BP121H" for the filter. I just used whatever I had in my tool box.

Now if you look at the size of the components, you'll notice that everything is tiny.
Don't attempt this mod if you aren't confident that you can do it!

Image
Rodrik
Posts: 18
Joined: Tue Jul 03, 2018 12:28 pm

Re: GBS 8200/8220 CFW Project

Post by Rodrik »

Ok, thank you.

I fully understand now. You maybe could put this picture in the git wiki with this explication to help others ones.
It's very tiny yes, so I will not attempt to do it yet without a microscope and of course I miss the parts :)
Instead I will power this card with a 5V 3A power supply vs a 9V now and will see if the noise issue has gone.

Rodrik
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

Definitely use a 5V supply, yeah.
It seems the 1117 oscillation doesn't start easily if the supply is 5V.
This doesn't apply to any of the later models, as they power their 1117 via the 3.3V regulated line.
I've no idea why they didn't do this on the first model as well. A mystery, like that Intersil IC :p
rama
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Re: GBS 8200/8220 CFW Project

Post by rama »

rama wrote: Also, they're making these now. It looks like the regular GBS board but with a VGA to HDMI transcoder slapped on.
Image
The TrueView is most likely still the same, so this should work right out of the box.
25 Euros delivered.
I got a slightly better test display now (NEC MultiSync EA190M), that accepts HDMI on its DVI input.
With this display I can confirm that the HDMI transcoder on these GBS boards doesn't affect the color mixing.
It dims the output a little, probably due to the passive components on its inputs. A small ADC gain correction (available on the Web UI) corrects it.

So, since the lag appears to be unaffected, this is probably the most convenient option for retro console > modern display now :)

Something to note on this particular GBS HDMI board is the power supply section:
It gets quite warm and the generated supply isn't as clean as on other boards by default.
My sample draws ~800mA at 5V input, for a total of 4W.
This is quite efficient, powering the scaler IC, ESP8266 with WiFi, SDRAM and HDMI Transcoder + extras.
However, the buck converter and its filtering is working hard in this configuration.
This is probably why someone made a newer revision of the GBS HDMI board, and they beefed up the power section.

Image

Both versions will work but if you plan on buying, look for the revised board.
Ryoandr
Posts: 269
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Re: GBS 8200/8220 CFW Project

Post by Ryoandr »

i can't see the programming jumper on the newest board.
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