shmups.system11.org

Shmups Forum
 
* FAQ    * Search
 * Register  * Login 
It is currently Tue Apr 13, 2021 10:25 pm View unanswered posts
View active topics



Post new topic Reply to topic  [ 4123 posts ]  Go to page Previous  1 ... 132, 133, 134, 135, 136, 137, 138  Next
Author Message
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 1:40 pm 


User avatar

Joined: 31 Oct 2016
Posts: 1344
Location: bmore
Josh128 wrote:
Its interesting. Not all colors are impacted by the issue, several are but some less than others. The primary color blue is definitely the worst. When looking a solid patch of true blue, its almost as if there are no scanlines at all! Light /sky blue is fine, with nice defined lines, but the closer to primary you get, the worse the issue. Primary red is next. There are still visible scanlines, but they are quite attenuated. Magenta is also affected but oddly enough, seems to be a bit better than pure red. Primary green seems to be the least affected, but the scanlines in it are definitely less pronounced than in pure whites , yellows, sky blues, and grays, which are the least affected.


This could suggest some kind of resonance with the specific frequencies represented by the effected colors that is causing ringing. Who really knows why it's happening (that could take a billion years on a scope to figure out), but you might be able to mitigate it with a couple of RC filters or an inductor or two. That is, if you are actually looking to clean it up. Also, I would wager that these devices are built with relatively shitty components with less than ideal values to save as much cents as possible. Beefing it up a little bit might improve it a bit.

Sorry if I'm being lazy and this was technically explained further back, but it seems like it could be fixed, especially because it's limited to certain colors.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 3:14 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
fernan1234 wrote:
but it's also kind of backward because on a CRT something like white would precisely have less space between the scanlines (or put in other words, the blank "scanlines" would be thinner). Whereas blue lines would definitely be thinner (or thicker blank "scanlines" in between blue).



It is kind of backwards in a way, as whites should have the thinnest blank lines. Its not completely backwards though because if you take white and go down the scale to dark gray, the blank lines do get thicker, so it reacts to intensity as a CRT would in that way (for a given color), but for certain colors the color itself takes more precedence for blank line intensity over the perceived luminance of any given color. Keep in mind this is how it reacts on a real SVGA CRT, I have no clue how it would change on an LCD.

It would be cool to be able to figure out what exactly is causing this behavior, but really, its not that much of an issue, at least on real CRTs IMO. The incredible advantages of this project far outweigh this one odd issue to me. The added lag of this thing is non-existent. I played with the manual lag tests and was able to get it perfect very easily. Being able to reposition the screen or being able to add additional vertical or horizontal stretch over what the monitor controls do is great. Add to that multiple supported output resolutions, downscaling, and adjustable scanlines and multiple save slots for profiles and real time wifi interface it really is something else. The fact that even a cheap OSSC costs 4x as much as a GBS-Control is also really pretty wild.

I think what Rama has done here is really big, and makes me wonder if he can pull off a few more tricks with the hardware. Theres two things on my wish list that may or may not be possible--

1.) Implement a straight up frame doubling 31KHz 240p120Hz mode. This would theoretically eliminate the odd color scanline issues as it would have real blank lines instead of fake.

2.) Implement a 1024x768 or 1366x768 mode where 15KHz sources could be line tripled to 720 pixels and centered on the screen leaving 24 blank pixels on top and 24 on bottom to allow for perfect scaling on 768p sets. In this mode, allowing a 2 to 1 vertical pixel ratio for scanlines to blank lines would give the 240p look to 768p displays.

I know the above are my wishlists for the OSSC Pro (and yes from what I understand the original OSSC can do #2 already), but man if these could be worked out on this little cheap device it would be crazy.


Last edited by Josh128 on Mon Mar 08, 2021 3:44 pm, edited 2 times in total.

Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 3:41 pm 



Joined: 14 Aug 2017
Posts: 1316
Totally agreed. For me, if I could only live with one single retro gaming scaling solution, it would be the GBSC, mainly due to its ability to handle scan rate changes seamlessly and with great picture quality throughout. I'm still very impressed with how CRT-like it is when a game switches from 240p with scanlines to 480i with bob+scanlines. The OSSC Pro probably will make this obsolete (and perhaps the RT5X Pro also, depending on how versatile it will be), but at a premium cost.

I actually don't use my GBSC as I still have a great multiformat CRT. But the GBSC is insurance, for peace of mind that it's ready to provide a close-enough experience with acceptable compromises.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 3:50 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
fernan1234 wrote:
The OSSC Pro probably will make this obsolete (and perhaps the RT5X Pro also, depending on how versatile it will be), but at a premium cost.


lol yeah, technically, perhaps, if it can match the speed of this and of course it will be far more versatile, but bang for the buck, it'll never come close to this little beast, I dont know if anything else ever will! :mrgreen:

Hey, a question-- does the DE-15 input on the GBS expect H and V sync or can you just feed C-sync to the H sync pin? Im looking to build a cable but if I can just pass through the sync to the proper pin I wont worry about putting a sync stripper or combiner or anything in the cable. Do you know?


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 5:15 pm 



Joined: 12 Jun 2017
Posts: 250
GBS-C will actually work better with csync (or a signal with embedded sync like luma or composite), fed on the H sync pin. It has currently troubles with HV sync signals.
Also don't forget RGB in can be also done through the big pins or the JST connector, which comes with the GBS. I used mine to a female scart socket. Just be sure to only use 1 method, as all share the same RGBHV pins !


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 5:33 pm 


User avatar

Joined: 09 Apr 2014
Posts: 453
Location: UK
Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 6:26 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
^^
Fantastic news !

I checked on the Github page and it seems that Rama suggests adding a 100 ohm resistor in parallel to the existing 500 ohm resistor from sync input to ground. This should bring the sync pin input impedance down to ~83 ohms (close to the ideal 75). Makes sense because H and V sync on VGA are TTL level (3-5V) while console sync output is generally 75 ohm level (.7V).

This makes sense because the console sync might not be able to driver the higher input TTL impedance.

https://github.com/ramapcsx2/gbs-contro ... c-stripper
Quote:
Sync (no extra sync stripper)
Every GBS board comes with ~500 Ohm termination on the sync input.
This termination is meant for (PC) VGA and most arcade boards. It is unfit for most other sources however.
If you want to use the RGBS input for regular TV level sources (game consoles), the GBS requires one additional 100 Ohm resistor to ground on the sync input.
Together with the factory resistor of ~500 Ohm, this will bring the total termination close to TV levels of 75 Ohm.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 8:37 pm 



Joined: 14 Aug 2017
Posts: 1316
Does anyone have instructions for updating the GBSC, for the sake of plebs like me who didn't go through the building process but simply bought one ready-made?


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Mon Mar 08, 2021 9:32 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
fernan1234 wrote:
Does anyone have instructions for updating the GBSC, for the sake of plebs like me who didn't go through the building process but simply bought one ready-made?


All you need is a USB cable to connect to the Arduino in your GBSC and a PC to download and run the Arduino software. You will then need to download the newest program available to compile with the Arduino software and push/upload to the Arduino.

Same as basic setup below, but you need the updated files containing the new web interface.

https://github.com/ramapcsx2/gbs-contro ... ware-Setup


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 12:09 am 



Joined: 14 Aug 2017
Posts: 1316
Josh128 wrote:
Same as basic setup below, but you need the updated files containing the new web interface.


Thanks for the pointers! Seems like it should be simple enough to figure out the first time.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 12:02 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
Ran across the wifi connection issue yesterday-- and found something interesting. I was sitting 5' away from the GBS and had no trouble at all connecting with my phone and my laptop PC (at the same time) when I was running an output res of 640x480.

I decided to play around and switched the output to 1280x1024, and I immediately began having near constant dropouts/connection issues on both the phone and the PC. It was so bad that I didnt think I would be able to switch the resolution back, so I shut off the monitor, thinking maybe some of the apparent interference was coming from there. After doing so, I was able to connect long enough to switch back to 640x480. I switched the monitor back on and my connection was rock solid. Not a single dropout on either device. The one thing I didnt do was really get an idea of how much shutting off the monitor helped, ie, I didnt play around in the menus very long, I immediately switched back to 640x480 at the first opportunity, so Im not certain if the interference originated from the monitor or the GBS-C itself at that resolution.

I do have access to an Anritsu SiteMaster spec an, if I can procure a 2.4GHz antenna I might be able to use it to see if I can see anything.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 12:06 pm 



Joined: 17 Mar 2018
Posts: 155
Location: Germany
I was having the same issue with mine: WiFi dropouts when using a 480p source.
I soldered a small piece of component leg to the PCB's printed antenna and now it's working stable.

I know that technically, the antenna's length is wavelength dependant, but I tried it anyway and saw a significant improvement.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 1:09 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
The wavelength of 2.4GHz radio waves are ~12.4 cm, so the ~2.5 cm antenna trace on that Arduino is not actually that length anyways. Its likely 1/4 wl + ground plane of the Arduino board. Adding any material will change both the impedance and polarization of the antenna, depending on the orientation of the wire you added (vert/horiz, cross, etc).

Its hard to say how the wire you added affected it, but its likely it changed (reduced) the match efficiency of the antenna, thus creating more isolation vs the interference AND the desired signal, but since the interference is likely spurious/harmonics and of lower amplitude than the desired signal, it was probably enough to to reduce/prevent the interference from it.

I need to go back and test, but Im curious if the interference originates from the CRT circuitry at a certain freq or the GBS scaler chip/board itself. Im pretty confident I can reproduce the problem easily to test.
Very interesting.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 2:06 pm 



Joined: 08 Mar 2017
Posts: 1373
Hey, the interference is from the large ASIC that locks on many transistors to the horizontal PLL (ADC sampling step).
This is a pretty large power draw PLL, so lots of switching at a frequency which's harmonics must be landing on the used WiFi channel.

If you have any experience with antenna design, we have plenty power to reach an AP even with a "bad" antenna, but that switching noise can completely drown the WiFi channel in the close distance to the ASIC that the ESP has to sit.
Anything that helps it receive / push through the noise will probably fix the worst of it.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 2:23 pm 



Joined: 08 Mar 2017
Posts: 1373
The H-PLL dependency means that the interference is closely related to the source sync timings.
A change from 240p to 480i for example is enough to unblock a channel.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Tue Mar 09, 2021 2:31 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
So the interference is from the ASIC shown here, but seemingly only at certain resolution outputs? I guess I could have rotated the Arduino 180degrees so that the antenna would be further from the ASIC, but that would have made the wiring more messy. I do have some Ultraperm 80 permalloy that I could use to create shielding, I'd just have to insulate it with kapton tape or saran wrap.

Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Wed Mar 10, 2021 9:22 pm 


User avatar

Joined: 21 Apr 2020
Posts: 14
Does someone know if the clock generators fit well in this case?

https://www.thingiverse.com/thing:4666227


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 12:20 am 



Joined: 06 Feb 2021
Posts: 1
Does anybody know if this can put the 960p signal from an OSSC in a 1080p window?

Or alternatively, how is its handling of 480p compared to the OSSC's line double?


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 3:14 am 


User avatar

Joined: 16 Jan 2014
Posts: 1221
Well, if you look in the picture showing FFIV on the monitor, the GBS has the clock gen board on the ASIC heatsink, so I would assume it does.

Looks great. I dont know how to feel about the BNC connectors though. A female SCART would have been much more useful IMO. Every RGB capable console I have uses a male SCART ended cable. This would require yet another adaptor cable, like the one below.

https://www.ebay.com/itm/193398140176?c ... zhEALw_wcB


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 7:35 am 



Joined: 04 Apr 2019
Posts: 2
Hello everyone

I have a little problem with a gbscontrol the Dreamcast does not sync.

Thanks

Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 12:43 pm 


User avatar

Joined: 21 Apr 2020
Posts: 14
Josh128 wrote:
Well, if you look in the picture showing FFIV on the monitor, the GBS has the clock gen board on the ASIC heatsink, so I would assume it does.

Looks great. I dont know how to feel about the BNC connectors though. A female SCART would have been much more useful IMO. Every RGB capable console I have uses a male SCART ended cable. This would require yet another adaptor cable, like the one below.

https://www.ebay.com/itm/193398140176?c ... zhEALw_wcB

Thanks, I didn't notice it lol.

https://www.thingiverse.com/thing:4771721 Here is Scart and HDMI version.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 2:25 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
The SCART and HDMI version looks like it still has the DE-15 ports that would work for me-- but how does one go about getting HDMI out and retaining the DE-15 out on this board? Do you have to use a modified 8220 board?


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 3:12 pm 


User avatar

Joined: 07 May 2018
Posts: 734
Location: Escondido, CA, USA
shinzuka wrote:
Hello everyone

I have a little problem with a gbscontrol the Dreamcast does not sync.

Thanks

Image
If you have the 100 ohm resistor between sync and ground, you will need to remove it for any vga sources.

Sent from my SM-G955U using Tapatalk


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 4:51 pm 


User avatar

Joined: 05 Apr 2017
Posts: 131
Location: TX
shinzuka wrote:
Hello everyone

I have a little problem with a gbscontrol the Dreamcast does not sync.

Thanks

Image


This is not a little problem.

I was never able to get my GBS-C to play nicely with my Dreamcast. It wouldn't work at 480p over DE15, and it wouldn't work at 480i over SCART on the 5-pin input. I tried removing the resistor and it made no difference.

I had to flag your image as offensive/adult because you have a computer desk with nowhere to put your legs, your MegaDrive appears to be some sort of ethereal phantasm, and of course your prominently featured webcam. Is this some weird way to promote your OnlyFans channel? I find this all to be very offensive/adult.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 8:56 pm 


User avatar

Joined: 21 Apr 2020
Posts: 14
Josh128 wrote:
The SCART and HDMI version looks like it still has the DE-15 ports that would work for me-- but how does one go about getting HDMI out and retaining the DE-15 out on this board? Do you have to use a modified 8220 board?

I saw some people mention that you can solder those WII2HDMI adapters directly to the GBS-8200, you can probably do the same with VGA to HDMI adapters.


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Thu Mar 11, 2021 11:59 pm 


User avatar

Joined: 05 Nov 2019
Posts: 707
Location: Massachusetts, USA
I almost wish GBSC would straight-up not support RGBHV inputs anymore, heh - someone really needs to design a cheap sync combiner dongle that you cram onto the DE-15 input. RGBHV seems to be wonky a lot of the time, even if you remove the 100ohm resistor!

And, hell, might as well come in a set of 2 - cram one on the output too!
_________________
For CRTs, A/V gear, video games & more, be sure to check out my eBay!

Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 12, 2021 12:50 pm 


User avatar

Joined: 16 Jan 2014
Posts: 1221
Stalked Rama on Twitter with some "wish list" questions for the GBS Control project. I was amazed by his answers! I know he is very busy and neither of these items are high on his priority list, but even the possibility of a 240p120 output gives me a thread of hope. If more coders / software engineers (it is open source) would take up the cause this already impressive little box could possibly do some even more amazing things!

Spoiler: show
Image


Liked the thingiverse case (with SCART input) posted above so much I asked my good buddy @OverlordManny who also CNC etched this for me last year if he could print one for me and he's already on it.

Spoiler: show
Image


Spoiler: show
Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 12, 2021 6:20 pm 


User avatar

Joined: 07 May 2018
Posts: 734
Location: Escondido, CA, USA
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.

Separately, I also soldered a wii2hdmi on to the output of a gbs and the results were very poor. Not centered image, lots of noise, very washed out. I tested the wii2hdmi before disassembling it and bodging, and it worked fine out of the box, used as intended with a wii.

I dont discourage others trying either of these. Just sharing my unimpressive results on both. Possibly a better sync combiner circuit could produce a better integrated solution.

Sent from my SM-G955U using Tapatalk


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 12, 2021 6:32 pm 


User avatar

Joined: 05 Nov 2019
Posts: 707
Location: Massachusetts, USA
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.

Separately, I also soldered a wii2hdmi on to the output of a gbs and the results were very poor. Not centered image, lots of noise, very washed out. I tested the wii2hdmi before disassembling it and bodging, and it worked fine out of the box, used as intended with a wii.

I dont discourage others trying either of these. Just sharing my unimpressive results on both. Possibly a better sync combiner circuit could produce a better integrated solution.

Sent from my SM-G955U using Tapatalk


An Extron interface seems to be the best bet for combining sync for higher (31+kHz) res RGBHV inputs - my passive Tektronix sync combiner is fine on the *output* but finicky on the input
_________________
For CRTs, A/V gear, video games & more, be sure to check out my eBay!

Image


Top
 Offline Profile  
 
 Post subject: Re: GBS 8200/8220 CFW Project
PostPosted: Fri Mar 12, 2021 10:04 pm 


User avatar

Joined: 27 Dec 2019
Posts: 18
I'm using this sync combiner https://dcemulation.org/?title=Dreamcas ... ster_Cable

Dreamcast 480p works great.


Top
 Offline Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4123 posts ]  Go to page Previous  1 ... 132, 133, 134, 135, 136, 137, 138  Next

All times are UTC


Who is online

Users browsing this forum: abispac, Foxe, Lux and 17 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Space Pilot 3K template by Jakob Persson
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group