GBS-8220, 23DB Connectors and Leads

[Higgy]

Originally Posted by dooklink

I wonder if anyone has specks in the normal operating settings though

Do you mean with just the normal GBS-, no RPi attached?

If so I have had speckles. As this lead me down the re-capping & decent PSU route (these 'fixes' I believe have now been proved to be a placbo!).

[dooklink]

Originally Posted by Higgy

Do you mean with just the normal GBS-, no RPi attached?

If so I have had speckles. As this lead me down the re-capping & decent PSU route (these 'fixes' I believe have now been proved to be a placbo!).

No I mean using my settings. I expect speckles in the pi menu, but not through the RGB input.

[Higgy]

Originally Posted by dooklink

No I mean using my settings. I expect speckles in the pi menu, but not through the RGB input.

Sorry, re-reading I don't think I was too clear in my earlier statement, I have changed it:

@dooklink - some info regarding speckles. I have just been playing about 4 AMIGA games with lots of black backgrounds, and I also ran a number of demoscene demos. And on my GBS-8220 v3 with the Hynix memory I am getting NO speckles on the AMIGA with your settings, but I have speckles on your menu.

Swapping from AMIGA to your menu seems to generate a lot of speckles initially, they then seem to die down a bit?

I am using Option 7 - RGBHV_720x576@50Hz_RGB_576i50_No_Scaling

Wow, just came here after reading Ian's blog (he linked here), and am totally amazed by the work that's been done

I complained about the movement distortion that people have mainly been looking to tackle here, looks like part 2 of his writeup is going to be all about that.

Originally Posted by Higgy

I have seen V4.0 pictures showing a 'samsung' chip.

I have a V4 8200 with a Samsung chip, it's a K4S643232C-TC80. I've never seen any speckles on mine, completely stock, so it must be a hardier or higher-rated chip.

[dooklink]

Finally got my stuff to gether and posted v0.2 sucessfully.
Should fix speckles in the RPi menu.
Also, I'd like someone to test installation on a rev1 Model B if possible as I don't have one to test my fix on.

[Higgy]

No problem I should be able to test this later today on my Rev 1 B.
Thanks.

[Higgy]

More DIY done. Dinner eaten. Time for AMIGA!!!

I did not do a complete new install on my RPi but updating to 0.2 worked great on my Rev 1 Model B. It's all looking sweet on my older LED monitor running 800x600@60Hz - 288p 50Hz. Just need some adaptive coding to alter res when the AMIGA jumps to Interlace mode (??? x 512 res) as at the moment the screen becomes corrupt as these res.

One comment I would make is put a Program version in your menu page, this way people can be sure of what version they are running.

Cheers.

P.S. And now no speckles in menu

[dooklink]

Originally Posted by Higgy

More DIY done. Dinner eaten. Time for AMIGA!!!

I did not do a complete new install on my RPi but updating to 0.2 worked great on my Rev 1 Model B. It's all looking sweet on my older LED monitor running 800x600@60Hz - 288p 50Hz. Just need some adaptive coding to alter res when the AMIGA jumps to Interlace mode (??? x 512 res) as at the moment the screen becomes corrupt as these res.

One comment I would make is put a Program version in your menu page, this way people can be sure of what version they are running.

Cheers.

P.S. And now no speckles in menu

I'm getting some good suggestions now both here, on the shmups forum and via email. So it looks like I've got some more unplanned work to do, haha.

[Higgy]

Yeah we the (AMIGA lot) should write a concise 'ideal wish list' on resolutions.

I expect @Stedy is busy in the background working on parts of this, but he will be best for 'the list'.

Where as most LCD TV's are going to be 720p or 1080p, a lot of AMIGA's will be run not off a TV but a lcd monitor. I have a question, on your settings there are quite a few outputs (sorry I don't have them in front of me now) but something like 640x480, 768x??? & 800x600. As they are all LCD, are they all 60Hz? The whole PAL\NTSC is now not relevant?
What is the benefit of say selecting 640x480? Do we just want to select the particular monitor's native or recommended resolution? Most 4:3 monitors seem to be 1024x768, or does outputting a lower res make less work for the GBS- .
Final question! Your settings has output freq and input freq. So I should always be selecting 50Hz for the input as I have PAL AMIGA, but the LCD monitor is only 60Hz? I guess this is the magic of the GBS-?

Thanks again. This is all very interesting stuff, shame its not my subject as I like to learn!

[dooklink]

Originally Posted by Higgy

Yeah we the (AMIGA lot) should write a concise 'ideal wish list' on resolutions.

I expect @Stedy is busy in the background working on parts of this, but he will be best for 'the list'.

Where as most LCD TV's are going to be 720p or 1080p, a lot of AMIGA's will be run not off a TV but a lcd monitor. I have a question, on your settings there are quite a few outputs (sorry I don't have them in front of me now) but something like 640x480, 768x??? & 800x600. As they are all LCD, are they all 60Hz? The whole PAL\NTSC is now not relevant?
What is the benefit of say selecting 640x480? Do we just want to select the particular monitor's native or recommended resolution? Most 4:3 monitors seem to be 1024x768, or does outputting a lower res make less work for the GBS- .
Final question! Your settings has output freq and input freq. So I should always be selecting 50Hz for the input as I have PAL AMIGA, but the LCD monitor is only 60Hz? I guess this is the magic of the GBS-?

Thanks again. This is all very interesting stuff, shame its not my subject as I like to learn!

My setting always specify input and output lines and refresh rate. The horizontal resolution is not really "correct" but there as a guide for people used to that. This is why the component modes don't list a hres.

There are no VESA 50Hz modes, so PC monitors usually don't accept 50Hz. The GBS will do the frame rate conversion, but it doesn't do a great job.

I prefer the component 50Hz output modes myself for PAL consoles. I'm only really interested in using the strict line doublef modes as I use a scanline generator.

[Stedy]

I tried the 0.2 software yesterday and the GBS-8200 would not sync to my Amiga . From memory I tried presets 6 and 8 and either got a rolling picture or static image.

I tried changing from Composite sync to separate Horizontal and Vertical Syncs and shifting the wiring. This did not work with the original Gonbes software or the 0.2 software. Weird. Will double check the scripts are correct for a Rev 1 model B Raspberry Pi.

I was using my A1200, which works with the original Gonbes software settings. I need to poke around inside the device, see what it thought it was seeing from my Amiga.

@Higgy

Do you use just a CSync signal from the Amiga?

@thread

A complication in getting the scaling/output right is that there are two scalers at work. One in the TVIA-5725 on the GBS-8200, the other in the TV/Monitor. A native 800x600 or 1024x768 display monitor would be ideal, as you would then only have one scaler to be wary of.

When time allows, I have been reading up on 50/60Hz conversion principles and what the GBS-82XX could achieve, it's educational.

Also have a couple of LMH1980 sync strippers to play with, now they are soldered to a VSSOP to DIL adaptor, they are easier to use.

Ian

[Higgy]

Hi,

Should just be CSync as per your SCART cable design.
I can see here that I have 6 WIRES going into my GBS-.

I'm really impressed with the improvements to the GBS-8200 that are being explored by your forum's members. This is really interesting and outstanding work. I registered to come here and thank everyone for testing and documenting their findings

I came across this thread a while back when I was diagnosing the white specks problem with my GBS-8200 (along with heat waves, sync issues, sprite flickering, and other video quality issues).

I wanted to bring here the solutions that worked for me, because I've seen a few people questioning if re-capping could be a possible solution. For my unit, the results were night and day. Additionally, I tried a few different power supplies and found that one resulted in a cleaner video signal, despite that they were both high-quality regulated-voltage/switching PSUs.

I have my GBS-8200 set up with Scart RGB inputs and an LM-1881 sync stripper. I have (US) Sega Saturns, SNES, Genesis/32x/CD (and soon, a TG16 after I complete its RGB mod). After the recap and power supply swap, the video quality is absolutely perfect. None of the original white specs remain, and the picture quality is much improved.

I've documented the solutions that worked for me here. It's pretty basic work compared to what is happening here at EAB though.

Originally Posted by dooklink

Just fitted a 10k and 22k resistor devider on my LM1881 output. Measured at just below 3V, works fine .

Ian Stedman recommends a 680 ohm series resistor. Is this a better choice?

The one problem that I have with my GBS-8200 its video signal dropping in some Japanese Saturn game menus. Is it possible that the SDRAM's incorrect timing could be the cause?

[giantclam]

....has there been any effort taken to document the actual sdram chips used on these things? I notice my v4 gbs8200 has a samsung K4S643232H-UC60 which is faster than a -TC80 variant noted above ; there's subtle differences. Just musings in my mind trying to explain disparities in performance between units (and looking for some definitive clue as to what's a real Gonbes board vs knock-off)...

[dooklink]

Originally Posted by giantclam

....has there been any effort taken to document the actual sdram chips used on these things? I notice my v4 gbs8200 has a samsung K4S643232H-UC60 which is faster than a -TC80 variant noted above ; there's subtle differences. Just musings in my mind trying to explain disparities in performance between units (and looking for some definitive clue as to what's a real Gonbes board vs knock-off)...

It's a good point, but It would be tough to know how many different versions there are of the PCB revisions. Then there are differences in brands used for ram and capacitors etc. It would be hard to know if there are multiple factories prodcing these, or if it is just one.

I've got dumps of two different firmware versions. Once I'm done with the next version of gbs-control I might write some more user-friendly scripts to dump the firmware and make checksums so we can compare them.

[kipper2k]

Need a spreadsheet guru to create a table with all necessary columns to identify different versions/results etc

[kipper2k]

Hi Smokemonster

Welcome to EB,

The Aluminium caps i like to use Panasonic, they are definately not the cheapest and i consider them the cleanest most stable caps i have found (fromDigikey)

Would a snap on choke on the cable help with cleaning up interference ?

Originally Posted by smokemonster

I wanted to bring here the solutions that worked for me, because I've seen a few people questioning if re-capping could be a possible solution. For my unit, the results were night and day. Additionally, I tried a few different power supplies and found that one resulted in a cleaner video signal, despite that they were both high-quality regulated-voltage/switching PSUs.


I've documented the solutions that worked for me here. It's pretty basic work compared to what is happening here at EAB though.


Ian Stedman recommends a 680 ohm series resistor. Is this a better choice?

The one problem that I have with my GBS-8200 its video signal dropping in some Japanese Saturn game menus. Is it possible that the SDRAM's incorrect timing could be the cause?

Originally Posted by kipper2k

Hi Smokemonster

Welcome to EB,

The Aluminium caps i like to use Panasonic, they are definately not the cheapest and i consider them the cleanest most stable caps i have found (fromDigikey)

Would a snap on choke on the cable help with cleaning up interference ?

I think you misread my post. I too was able to clean up the noise and white specs by recapping with higher quality parts

[kipper2k]

Originally Posted by smokemonster

I think you misread my post. I too was able to clean up the noise and white specs by recapping with higher quality parts

nope, i didnt misread it, i was just wondering if a choke would help also, and saying that i think Panasonic also make good quality replacements

[alexh]

I don't know if anyone cares but it looks like there is now a similar board with integrated HDMI

http://timeharvest.net/new-arrival-c...ine-p-706.html