GBS 8200/8220 CFW Project

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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

sanni wrote:Could you also send the i2c commands with a $5 Arduino or does it need the power of a linux operating system?
There is no reason you couldn't, but you might need some external storage. I just used the pi for testing as I had one. It also helped to use the composite video out in B&W as a menu. This means I have my own stand alone setup with just a keyboard and the PCBs.
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emphatic
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Re: GBS 8200/8220 CFW Project

Post by emphatic »

This is such a cool project you've created. Kudos!
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ikari_01
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Re: GBS 8200/8220 CFW Project

Post by ikari_01 »

I've fiddled around a bit as well. There seem to be a fair number of undocumented registers (e.g. a register which controls horizontal green shift).
Did you have any success with SDRAM bypass (i.e. direct deinterlace -> video processor, without using the framebuffer)? I always get massive jitter no matter what I try. Same with sync lock mode. I can't seem to get the clocks in phase properly.
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

ikari_01 wrote:I've fiddled around a bit as well. There seem to be a fair number of undocumented registers (e.g. a register which controls horizontal green shift).
Did you have any success with SDRAM bypass (i.e. direct deinterlace -> video processor, without using the framebuffer)? I always get massive jitter no matter what I try. Same with sync lock mode. I can't seem to get the clocks in phase properly.
Yeah the undocumented registers are a real pain. I've tried using the frame lock mode, but it doesn't really work as expected. The sync lock mode means you have to have identical output and input resolution/frequencies, so I don't think it can do scalling.
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Ms. Tea
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Re: GBS 8200/8220 CFW Project

Post by Ms. Tea »

This is a really, really cool project. Kudos for your work on it!!

I'd be very curious to see a direct capture of the linedoubled output, if anyone's able to do that.
fluxcore
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Re: GBS 8200/8220 CFW Project

Post by fluxcore »

Very cool project. I would be extremely happy even with just the following:

50Hz support (I'm in PAL territory and this would be quite useful, and my board certainly doesn't support it 'natively')
Midway board support (jammaboards 'custom' firmware - the board I have has it, and retaining this is very important to me)
Disabling that stupid logo screen upon startup - it obscures arcade board revision information when both are powered from the same source :(

A 'linedoubler only' mode would be pretty nifty too.

Keep it up!
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KevinDDR
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Re: GBS 8200/8220 CFW Project

Post by KevinDDR »

Extremely extremely cool! I'll check it out soon! :)
blank964
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Re: GBS 8200/8220 CFW Project

Post by blank964 »

Excellent to see this. I'm following this on github now.

I'd love to try this out soon.
Last edited by blank964 on Sun Dec 07, 2014 7:44 am, edited 1 time in total.
blank964
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Re: GBS 8200/8220 CFW Project

Post by blank964 »

My plan this week is to make a super GBS 8200:

1) Recap the board with high quality caps
2) Setup this mod.

I'll report back when it's finished.
porga
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Re: GBS 8200/8220 CFW Project

Post by porga »

Dear friend,

if you succeed to remove artifacts from GBS output, you will make lots of Amiga users very happy. I think it is worth a shoot, even donations would be possible.

Look at this theme discussing GBS signal output.

http://eab.abime.net/showthread.php?t=66922&page=8
porga
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Re: GBS 8200/8220 CFW Project

Post by porga »

I just realize that you plan to use Raspbery Pi for GBS control? Is it possible to avid that and flash changed firmware directly to the board? GBS + raspbery pi complicates things a little, and adds to complexity.
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

I've been working on interfacing with the MTV230 micro and have got good news. I've just got some of my own assembly code working. I've written some really basic python scripts to read and write to the Code and OSD flash sections. I've dumped a version of the firmware and put a branch point in the code that swaps over to my own code when I pull a pin low, else it functions as normal.

Now I may have a long process of learning how the hardware functions like the OSD. Hopefully I'll write a little loader that can accept compiled C code appended to the end of the original firmware.
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yxkalle
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Re: GBS 8200/8220 CFW Project

Post by yxkalle »

Now that you've dumped the firmware, does it mean you can test things out without a risk of bricking it? Great work! :)
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emphatic
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Re: GBS 8200/8220 CFW Project

Post by emphatic »

Excellent update!
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RegalSin wrote:Street Fighters. We need to aviod them when we activate time accellerator.
DUPONTG
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Re: GBS 8200/8220 CFW Project

Post by DUPONTG »

hello,
thank you for the datasheet...
you can download the trueview 5725 programming guide here:
http://ul.to/rk74e3o5
Ace9921
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Re: GBS 8200/8220 CFW Project

Post by Ace9921 »

Would it be possible for the GBS-8220 to accept 240p RGB and output 1080p Component video without any deinterlacing applied? This could be of some use for a project I have in mind if you can make this happen.
blank964
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Re: GBS 8200/8220 CFW Project

Post by blank964 »

Intro
I think this is great work. I just set it up in about 15 minutes and the results look good I think.

Results
Image
Figure 1 Drop Shadow Test. I can confirm that drop shadow looks good (I'm not sure if the photo captures it). But it no longer has the interlaced lines when I move the object around.

Image
Figure 2 Manual Lag test. Fortunately manual lag test looks good.

Discussion
So I think now I just need to recap the board. I've got 2 Nippon 470uF and 5 100uF Illinois caps on their way. This should be a great board for $30. I mean a lagless, artifact free, 240p beast!

Methods
This was with the HD9800. I have a genuine GBS but thought it would be more interesting to try a knock-off first. Console was a model 1 genesis and a retro console accessories scart cable. There is also a sync stripper and a SLG 3000 attached. Screen is an ASUS PA246Q (my desktop monitor). Setup was as per dooklink's repo.
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

Ace9921 wrote:Would it be possible for the GBS-8220 to accept 240p RGB and output 1080p Component video without any deinterlacing applied? This could be of some use for a project I have in mind if you can make this happen.
I have been meaning to try this. I'll dump the settings from the HD Box Pro's 1080p output and see how that works. I'm not sure how the HD Box Pro is set-up for 1080p upscalling though.

@blank964:
Good to see someone trying the Raspi set-up. What do you hope to achieve with a recap? Let me know if that does improve anything cause I have my doubts.
Also, can you see any horizontal scalling artifacts. There shouldn't be any vertical artifacts, but I've found there is a light noise pattern horizontally.
It could be that your monitor cleans up the analogue signal better than mine though.
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Xyga
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Re: GBS 8200/8220 CFW Project

Post by Xyga »

Would a 'scanlines' feature be difficult to add to the fw ? (like the XRGB's line blanking)
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

Xyga wrote:Would a 'scanlines' feature be difficult to add to the fw ? (like the XRGB's line blanking)
I've thought about ways to do this, but I'm not sure it would be possible. I can think of two methods, one would be cutting traces to the ram to stop each second line from being read/writen, I don't think there is anyway to do this in the chip. The other method would be to use the OSD to blank every second line, but I don't think it has the required resolution.
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Xyga
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Re: GBS 8200/8220 CFW Project

Post by Xyga »

I see, thanks!
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blizzz
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Re: GBS 8200/8220 CFW Project

Post by blizzz »

There's a guy on another board (ikari_01) who hacked scanlines into the 8220 firmware. But he could only make them green.
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

blizzz wrote:There's a guy on another board (ikari_01) who hacked scanlines into the 8220 firmware. But he could only make them green.
Intresting. Do you know how? Was it a modification to the 5725 or the MTV230? I've seen similar glitches in the 5725 settings.
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blizzz
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Re: GBS 8200/8220 CFW Project

Post by blizzz »

Oh, I forgot that he's also on this board. He even posted on the first page of this thread xD

You could try asking him in PM. Doesn't look like he's coming here all that often.
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Xyga
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Re: GBS 8200/8220 CFW Project

Post by Xyga »

Isn't he the sd2snes guy ?
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blank964
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Re: GBS 8200/8220 CFW Project

Post by blank964 »

dooklink wrote:
Ace9921 wrote:Would it be possible for the GBS-8220 to accept 240p RGB and output 1080p Component video without any deinterlacing applied? This could be of some use for a project I have in mind if you can make this happen.
I have been meaning to try this. I'll dump the settings from the HD Box Pro's 1080p output and see how that works. I'm not sure how the HD Box Pro is set-up for 1080p upscalling though.

@blank964:
Good to see someone trying the Raspi set-up. What do you hope to achieve with a recap? Let me know if that does improve anything cause I have my doubts.
Also, can you see any horizontal scalling artifacts. There shouldn't be any vertical artifacts, but I've found there is a light noise pattern horizontally.
It could be that your monitor cleans up the analogue signal better than mine though.
There's some pixel flickering on high contrast edges otherwise I can't detect any problems with my eye. I'm replacing caps for better long term reliability and to see whether there are any image improvements (doubtful but possible).

Image
My version of the rpi gbs setup.
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

Just tested my RasPi setup with the SLG HD= from Arcadeforge.de and it works perfectly once I tweaked the sync output voltage a little higher.
I'll update my Github release with the new settings soon, they are in the develop branch if you want them now. You may still have to turn the SLG HD= off and on again when changing between 480p & 576p.

This finaly works how I wanted it to, line doubled 576p50Hz for RGB PAL consoles with scanlines via YPbPr component compatible with all HDTVs.
blank964
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Re: GBS 8200/8220 CFW Project

Post by blank964 »

I switched screens to a UN40EH5000 and a some feet of sofa distance. The pixel flicker on the mega drive (MD) is much less noticeable. I also tried a NTSC-U saturn, which was from what I could tell excellent (without pixel flickr). Now, I know the MD is rather temperamental and even the XRGB-mini requires boost on the sync strength. Do you have any ideas for MD specific improvements? I upped the input sync from the default of 4 to 8 and it may have helped (although it's hard to be sure).
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dooklink
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Re: GBS 8200/8220 CFW Project

Post by dooklink »

blank964 wrote:I switched screens to a UN40EH5000 and a some feet of sofa distance. The pixel flicker on the mega drive (MD) is much less noticeable. I also tried a NTSC-U saturn, which was from what I could tell excellent (without pixel flickr). Now, I know the MD is rather temperamental and even the XRGB-mini requires boost on the sync strength. Do you have any ideas for MD specific improvements? I upped the input sync from the default of 4 to 8 and it may have helped (although it's hard to be sure).
What do you mean input sync? Do you mean the coast values? I'm not even sure if those are working correctly it's been so long since I've needed them.
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ikari_01
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Re: GBS 8200/8220 CFW Project

Post by ikari_01 »

Xyga wrote:Isn't he the sd2snes guy ?
Indeed ;)
I got the GBS8220 to produce "scanlines" by setting If_ld_sel_prov to 1 (REG_S1_0b [7]) IIRC.
They are definitely unusable though, as the gaps between the picture lines are just "undefined" data, can be green, have yellow bars, etc.
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