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Author Topic: 15.7KHz composite sync generator  (Read 916 times)

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gambaman

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15.7KHz composite sync generator
« on: September 13, 2018, 02:04:58 pm »
I have designed yet another VGA to SCART adapter. The project has been published at https://hackaday.io/project/161006-yet-another-vga-to-scart-adapter. It uses a cheap PIC10F320/322 microcontroller featuring a configurable logic cell (CLC) to generate the composite sync signal. It has the following advantages:

  • It has only two components (the PIC and a resistor) and requires only 6 connections.
  • It automatically detects the polarity of the input sync signals and configure the CLC to generate the composite sync correctly.
  • The PIC monitors the input signal and set the composite sync to ground if the frequency of the horizontal sync signal is wrong or if the vertical sync signal does not change. This is useful if you are using it to generate the Csync signal of a very old arcade monitor to protect it.
  • With a few additional components it can also generate the RGB status signal, the shutdown signal of the DC-DC converter I use to generate 12V and provide visual indication of the correctness of the input signals.

Paradroid

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Re: 15.7KHz composite sync generator
« Reply #1 on: September 13, 2018, 05:00:13 pm »
I have designed yet another VGA to SCART adapter.

Wow! Great write-up! Looking forward to spending time to digest all this...
My MAME/SCART/CRT blog: SCART Hunter

buttersoft

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Re: 15.7KHz composite sync generator
« Reply #2 on: September 13, 2018, 09:15:30 pm »
Wow, looks good, thanks for sharing. I do have some questions though :)

If i were to program a pic, what should the fuses be set to?

I notice the frequency is set to NTSC (15.734kHz). Is there a reason you chose that over a PAL frequency? What are the scanrate cutoffs set to right now and how would i change them?

gambaman

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Re: 15.7KHz composite sync generator
« Reply #3 on: September 14, 2018, 09:33:32 am »
If i were to program a pic, what should the fuses be set to?

It depends of your project, I guess. For example the watchdog is not used in this project so I set WDTE off.

I notice the frequency is set to NTSC (15.734kHz). Is there a reason you chose that over a PAL frequency?
I was going to use the project for arcade emulation. I read in http://www.ultimarc.com/monfaq.html that "most available early monitors were based on TV designs and so had the same frequencies". Most old arcades I know are from USA or Japan so I chose the System M frequency. Anyway the frequencies of System M and PAL-B/G/H/I/N are very similar (15.734 kHz vs. 15.625 kHz), and since I programmed the PIC to allow a period tolerance of +-10% it should work using both frequencies.

What are the scanrate cutoffs set to right now and how would i change them?
The period of the horizontal sync must be between 90% and 110% of the nominal (more or less). To change the tolerance replace the string "9*_XTAL_FREQ/_hsync_FREQ/10/16" (for the minimal period) or the string "11*_XTAL_FREQ/_hsync_FREQ/10/16" (for the maximum period) in the source code.
« Last Edit: September 14, 2018, 10:58:08 am by gambaman »

Zebidee

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Re: 15.7KHz composite sync generator
« Reply #4 on: September 16, 2018, 12:34:57 pm »
Nice work. I also enjoyed looking over your other projects, quite a bit of creativity there  :cheers:

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nitrogen_widget

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Re: 15.7KHz composite sync generator
« Reply #5 on: September 18, 2018, 04:29:52 pm »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux



buttersoft

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Re: 15.7KHz composite sync generator
« Reply #6 on: September 18, 2018, 08:45:27 pm »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

No, the OP is not converting signal formats, really. He's just combining sync and adding a feature that detects the sync rate. It's a VGA to SCART adapter/converter. Component video is not part of this. Added to which the adapter you posted has a male scart end, so i'm not sure what you were planning to plug into what.

The period of the horizontal sync must be between 90% and 110% of the nominal (more or less). To change the tolerance replace the string "9*_XTAL_FREQ/_hsync_FREQ/10/16" (for the minimal period) or the string "11*_XTAL_FREQ/_hsync_FREQ/10/16" (for the maximum period) in the source code.

15.7kHz +/-10% is about 14.1 to 17.2, which is a huge range and easily enough to cover arcade monitors and 15kHz PVM's as well, so that's great. I'm not much for recompiling stuff :)

gambaman

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Re: 15.7KHz composite sync generator
« Reply #7 on: September 19, 2018, 07:17:33 am »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

Hi. I don't see the point in connecting a VGA-SCART adapter to a SCART-COMPONENT converter. If your TV does not have SCART but has a component input, wouldn't it be simpler and cheaper to use just a VGA-COMPONENT converter?

nitrogen_widget

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Re: 15.7KHz composite sync generator
« Reply #8 on: September 19, 2018, 08:56:37 am »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

No, the OP is not converting signal formats, really. He's just combining sync and adding a feature that detects the sync rate. It's a VGA to SCART adapter/converter. Component video is not part of this. Added to which the adapter you posted has a male scart end, so i'm not sure what you were planning to plug into what.


I got things I can plug it into. :)
seriously I have a scart cable that fits the adapter I have.
I've seen people on AV forum report feeding rgb from their classic console into one of those adapters and have it work on a component TV.
but I don't know enough about video and it's the internet so couple yr old posts on another forum don't help me too much so I thought i'd ask.

nitrogen_widget

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Re: 15.7KHz composite sync generator
« Reply #9 on: September 19, 2018, 09:29:55 am »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

Hi. I don't see the point in connecting a VGA-SCART adapter to a SCART-COMPONENT converter. If your TV does not have SCART but has a component input, wouldn't it be simpler and cheaper to use just a VGA-COMPONENT converter?

VGA to component adapters that work with low resolutions are hard to find.
It's why I asked.
I have an two old used extron device off ebay that will take VGA and turn it to RGB but the sync? I think is on the wrong color I guess because the rgb-scart to component adapter works but one gives me a lovely green tinted picture (clear though) and the other flickers badly if I recall correctly. it's been a few yrs.

I just dropped 96$ on a jrok rgb to component board so if this provided a true RGB- SCART signal it would be a lot cheaper if what I had in mind worked.
But I don't know enough about video to know if this could work or people are thinking "what is this guy smoking?" :)

It

gambaman

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Re: 15.7KHz composite sync generator
« Reply #10 on: September 19, 2018, 11:14:14 am »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

Hi. I don't see the point in connecting a VGA-SCART adapter to a SCART-COMPONENT converter. If your TV does not have SCART but has a component input, wouldn't it be simpler and cheaper to use just a VGA-COMPONENT converter?

VGA to component adapters that work with low resolutions are hard to find.
It's why I asked.
I have an two old used extron device off ebay that will take VGA and turn it to RGB but the sync?
Hi. Probably it is not a VGA to RGB converter since VGA is already RGB. If the output of the device has a red connector, a green connector and a blue connector then it is probably a VGA to component converter. In that case the sync signal (and the luma) is carried in the green connector.

About the converter of your link https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux: I am not sure, but I think that to get the YPbPr signals you must make ponderate sums of the RGB signals using operational amplifiers. The converter of the link does not look to have a power input to feed the operational amplifiers. Maybe they are fed using the RGB-status pin of the SCART connector. In that case the power source of the VGA-SCART adapter will be also feeding the SCART-COMPONENT converter. If it supplies enought current, you configure correctly your VGA card and the SCART-COMPONENT is mixing properly the red, green, blue and Csync signals then I think it may work. Anyway I know very little about video myself.
« Last Edit: September 19, 2018, 11:19:51 am by gambaman »

gambaman

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Re: 15.7KHz composite sync generator
« Reply #11 on: September 19, 2018, 06:47:35 pm »
Any ideas on if this circuit would work with a cheap SCART to component adapter on a component TV?
https://www.ebay.com/itm/RGB-SCART-to-Composite-COMPONENT-VIDEO-AV-TV-ADAPTER-HD-CONVERTER/222981233413?hash=item33eab79b05:g:FTMAAOSws65Tq7ux

Hi. I don't see the point in connecting a VGA-SCART adapter to a SCART-COMPONENT converter. If your TV does not have SCART but has a component input, wouldn't it be simpler and cheaper to use just a VGA-COMPONENT converter?

VGA to component adapters that work with low resolutions are hard to find.
It's why I asked.
I have an two old used extron device off ebay that will take VGA and turn it to RGB but the sync?
Hi. Probably it is not a VGA to RGB converter since VGA is already RGB. If the output of the device has a red connector, a green connector and a blue connector then it is probably a VGA to component converter. In that case the sync signal (and the luma) is carried in the green connector.

I have just read at wikipedia that I was wrong. There are RGB systems that use only for wires for the ground, red, green, blue and composite sync signals. The composite sync signal is overlaid on the wire used to transport one of the components. Of these systems, the most common is sync on green (SoG). SoG uses the same wire for the composite sync and the green component. According to wikipedia:
Quote
A monitor that is not equipped to handle SoG will display an image with an extreme green tint, if any image at all, when given a SoG input.
That is what happened with one of your adapters so I think it is a VGA-SoG converter.

gambaman

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Re: 15.7KHz composite sync generator
« Reply #12 on: September 19, 2018, 10:13:04 pm »
I just dropped 96$ on a jrok rgb to component board

I have looked at it and it requires a 15KHz composite sync signal as well as the red, green and blue signals. I think you can connect the red, green and blue signals directly to your VGA and use my design to generate the composite sync signal. I have read that the jamma maximun Csync voltage is 5V so I would use a voltage divider at the output of the PIC just in case. A pair of 1K ohm series resistor should be OK. Place them like this:


Note that you will have to configure the VGA for a frequency of 15.7Khz.
« Last Edit: September 19, 2018, 11:05:02 pm by gambaman »

Zebidee

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Re: 15.7KHz composite sync generator
« Reply #13 on: September 19, 2018, 10:36:26 pm »
Sync on Green is a standard used for SCART input, but I've never come across a SCART TV that demands this in preference to full RGBS.

SoG is different to component (YPbPr) in that the green "chroma" is still present on the G line (TV must know how to separate it out). With component, the "Y" (green wire) carries just luma (brightness) & sync, no green. The green is not actually present at all, and green is determined by the TV using simple calculus/algebra as it already knows blue (-luma) and red (-luma) & luma.

I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit. My electronics skills aren't good enough (yet) to design such a circuit, but I could build one. There would be an awful lot of retrogaming people interested in building it.

I've also been looking at how to get component out of a PC *without* needing a converter. Some video cards support component out, but it is designed for HDTVs and video projectors that can display VGA/~31khz modes normally output by PCs like 480p, 720p and 1080p. The reason for providing this support is that these HDTVs and projectors were used a lot in business (presentations etc) and home theatre applications, but this is less common now. For us, a problem arises because SDTVs (which we prefer for retrogaming) that accept component inputs cannot display these modes.

Another problem is that it is difficult to work out just which video cards support component out in the first place. Mostly it seems to be older cards, I have no idea about newer cards. There are some NVIDIA cards that support component, but a lot more ATI/AMD cards seem to. In particular, cards with VIVO support seem to be component-capable. For example, AFAIK these old ATI cards support component out:

    ATI RADEON 9800 Series
    ATI RADEON 9700 Series
    ATI RADEON 9600 Series
    ATI RADEON 9500 Series
    ATI RADEON 8500 Series
    ATI RADEON 8500LE Series
    ATI ALL-IN-WONDER RADEON 9800 Series
    ATI ALL-IN-WONDER RADEON 9700 Series
    ATI ALL-IN-WONDER RADEON 9600 Series
    ATI ALL-IN-WONDER RADEON 8500
    ATI ALL-IN-WONDER RADEON 8500DV

I'd be very interested to know what modern video cards (if any) support component out, but information is very scarce.

Who cares if you can't produce an image on component SDTV? Well, you can. If your card is capable of outputting component video you are already halfway there, you just need to use another application like Powerstrip, CRT_emudriver or soft15khz to generate the 15khz modes. I've done this before with Powerstrip (long time ago) & a Radeon 9600 (iirc), but I see no clear reason why CRTEMU and soft15khz would not work like this as well. Note that these apps don't actually modify the video signal at all, they just generate modes for your card to output. Your video card does all the signal conversion for you already, if able to and configured properly.

Component video output from a compatible card will be available on the RGB signal outputs, you just need to add in ground and hack your VGA/DVI output to 3 RCA female connectors (or RCA/component cables with these male connectors on the other end). You can buy cheap, passive adapters on ebay etc for about $3. Or you can just build your own (AFAICT, all you'd need to patch through is RGB, ground. Sync is already on green). You might like to keep wires for VGA pins 11, 12 & 15 available (as these are used for monitor EDID info, which may (or may not) be needed by your video card).
https://www.ebay.com/itm/3-RCA-RGB-Video-Maschio-a-HD-15-Pin-VGA-Component-Video-Jack-Adattatore-Nero/282709683678?hash=item41d2cf6dde:g:nXoAAOSwWLBZ8rb~

Why not just buy an overpriced VGA-component converter? Well, if you like, I'm a cheapskate and don't understand why you have to buy new expensive stuff to play old games (which is the default advice I keep on hearing on these forums) when there are cheaper, possibly better options. Building it is probably easier. Plus it can be hard and expensive for me to get specialised electronic stuff where I am (rural Thailand). Out of the last 3 shipments of electronic stuff from overseas, customs intercepted 2 of them, charged me more in tax/bribes and caused delays/concerns from my suppliers. It is a PITA. However, this VGA-component converter does look attractive and is getting close to the right price range:
https://www.monoprice.com/product?p_id=8668

ATM, I don't even have a component input TV to test my theories on, but I do have a bunch of old video cards. I was stimulated to look into this recently by another poster who is from Columbia, who faces much worse problems than I do with getting stuff like VGA-component converters from overseas.

PS - you don't I don't think that you need a voltage divider on the 5v sync, but maybe it won't hurt. I've done heaps of SCART cables without needing to pull sync voltage down, had good results, and when I've tried using voltage dividers on sync it didn't help/caused problems so I removed it. Maybe I missed something.

EDIT - italics on the PS, last bit

PPS - If doing a voltage divider on sync, don't forget that video signals are normally 75 ohm terminated at the TV/monitor.
« Last Edit: September 19, 2018, 10:59:38 pm by Zebidee »
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buttersoft

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Re: 15.7KHz composite sync generator
« Reply #14 on: September 19, 2018, 10:49:32 pm »
Sync on Green is a standard used for SCART input

Is it? Where did you find that information? I've never heard that before.

I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit.

I've actually been talking with a guy on FB who is designing one. He sent me an update the other day, which i think should be the finished version. I'll see if I can dig something up Tonight.

gambaman

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Re: 15.7KHz composite sync generator
« Reply #15 on: September 19, 2018, 11:03:00 pm »

I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit.

I've actually been talking with a guy on FB who is designing one. He sent me an update the other day, which i think should be the finished version. I'll see if I can dig something up Tonight.

I am quite curious about that. Would it be possible for you to show the design?
« Last Edit: September 19, 2018, 11:07:16 pm by gambaman »

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Re: 15.7KHz composite sync generator
« Reply #16 on: September 19, 2018, 11:36:33 pm »
Sync on Green is a standard used for SCART input

Is it? Where did you find that information? I've never heard that before.

Buttersoft, just from general experience and reading on the subject, can't remember exactly where. I've never had to actually deal with a TV that only accepts SoG. AFAIK it isn't common, SoG was mostly a standard promoted by Sony with limited success. To save you googling, here is a more credible reference to SoG/SCART, I'm sure that there must be more/better if you spend more time looking:
http://www.datasheetarchive.com/pdf/download.php?id=72e946601bccf5284c723433e301904c499732&type=P&term=peritel

Quote
I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit.

I've actually been talking with a guy on FB who is designing one. He sent me an update the other day, which i think should be the finished version. I'll see if I can dig something up Tonight.

Wow, fantastic! Really looking forward to seeing it. I'm in Bangkok right now and will be hitting the electronics zones next week (distinct from the IT and gaming zones, which I'll probably hit on the weekend) so hope to be able to pick up much of what I need for this and other future projects.

Z.
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gambaman

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Re: 15.7KHz composite sync generator
« Reply #17 on: September 19, 2018, 11:42:26 pm »
PS - you don't I don't think that you need a voltage divider on the 5v sync

Hi, Zebidee. Do you mean this?:



I've done heaps of SCART cables without needing to pull sync voltage down, had good results, and when I've tried using voltage dividers on sync it didn't help/caused problems so I removed it. Maybe I missed something.[/i]
You do not need to pull it down because it will be pulled down by the 75 ohm internal resistance of the TV when you connect the adapter. You don't have to make the whole divider because it will be completed when you plug the adapter. In fact it will probably not work if you add another resistance, unless you also change the other resistance.

PPS - If doing a voltage divider on sync, don't forget that video signals are normally 75 ohm terminated at the TV/monitor.

It has been taken into account. The H value of the sync of the scart is about 0.3V, and 5V*75/(1000+75)=0.349V.

Anyway I have only implemented this design once, and I have tested it using an only TV. I would like to know if it worked for anybody else.
« Last Edit: September 19, 2018, 11:46:32 pm by gambaman »

Zebidee

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Re: 15.7KHz composite sync generator
« Reply #18 on: September 20, 2018, 02:54:01 am »
PS - you don't I don't think that you need a voltage divider on the 5v sync

Hi, Zebidee. Do you mean this?:
... [pic]
Quote
PPS - If doing a voltage divider on sync, don't forget that video signals are normally 75 ohm terminated at the TV/monitor.

It has been taken into account. The H value of the sync of the scart is about 0.3V, and 5V*75/(1000+75)=0.349V.

Anyway I have only implemented this design once, and I have tested it using an only TV. I would like to know if it worked for anybody else.

Originally I meant for JAMMA (5v sync) there is no need a video card sync signals max at 5v anyway. Maybe that isn't what you really meant.

In terms of SCART, your latter design (1*1k resistor in series) makes more sense given the 75 ohm termination, yes. But I thought the SCART sync standard was 1v? Or am I thinking something else? If aiming for 1v, wouldn't something like 1 * 300 ohms in series makes more sense? 5v is the max sync output we expect from the video card (usually peaks much less than this). Then you'd get 5V*75/(300+75)=1.0V (max). Am I reading this right?
eg: http://pinouts.ru/Home/Scart_pinout.shtml

You are going to think me a cowboy for saying this... Testing dozens of TVs, I've not yet met a TV that complains about video card sync levels (ie max 5v) through standard inputs. Maybe I've been spoiled by too many nice Sony's and nice Euro TVs (Grundig, Loewe, Thomson etc) from the "Golden Age" of TV scavenging. TVs usually seem to be flexible enough to accept a fair bit variation, and 5v is pretty low by most design standards, I guess so long as they can detect the relevant waveform within their tolerance/range.

Because I love being proven wrong... I've also experimented with our different forms of voltage dividers on PC sync => TV, never gave better/good results so I basically won't do it without a good reason. Regardless, I will be interested in any results you come up with.

Double up my cowboy points, I've also not yet met a TV that complains about composite sync from simply twisting the H+V sync lines together with the following caveat: So long as the source syncs are generated with the same polarity (note that ATI/AMD cards output negative on both by default, and that is what I usually use). Sync converters would be essential otherwise, and yes I love your work, don't worry. Moving on out of cowboy territory...

Aside from not blowing up/melting things, where the voltage levels are more critically important is with RGB/chroma/luma, as this will directly impact your screen image (ie higher voltage = brighter image). For example, that is why it is important to have a video amp if using PC => arcade monitor as the latter expects a stronger RGB (not stronger sync) signal. Even with a video amp, you may have to resort to new tricks to get a good signal (eg blooming), but that is the subject of another post I plan to make soon... :D




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gambaman

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Re: 15.7KHz composite sync generator
« Reply #19 on: September 20, 2018, 10:50:32 am »
Originally I meant for JAMMA (5v sync) there is no need a video card sync signals max at 5v anyway. Maybe that isn't what you really meant.

Hi, Zebidee. I think your are right. Even if the PIC is powered by a bit more than 5V, the output will be always lower. Also, the board receiving the signal must have a tolerance. I think I'm a paranoid  :embarassed:.The divider is probably helpless.

In terms of SCART, your latter design (1*1k resistor in series) makes more sense given the 75 ohm termination, yes. But I thought the SCART sync standard was 1v? Or am I thinking something else? If aiming for 1v, wouldn't something like 1 * 300 ohms in series makes more sense? 5v is the max sync output we expect from the video card (usually peaks much less than this). Then you'd get 5V*75/(300+75)=1.0V (max). Am I reading this right?
eg: http://pinouts.ru/Home/Scart_pinout.shtml

I think that the first table is not wrong, but is not complete. The signal levels are described in the third table of your link. The peak to peak voltage of pins 19 and 20 depends on their use. If they are going to be used to carry a composite video signal then it is 1V, but according to the official CENELEC standard EN 50049-1:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwi52qD93cndAhWKy4UKHUfQDQwQFjABegQIBRAC&url=http%3A%2F%2Ffr.meric.free.fr%2FArticles%2Farticlesba%2Fstsurtvplat%2FScart%2FBS_EN_50049-1%2520Peritelevision%2520connector.pdf&usg=AOvVaw07NPYxu6r-CYX7JCq_4bBe
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When the signal on this terminal is exclusively a synchronization signal, the peak to peak voltage is 0,3 V (23 dB, +10 dB)

P.D: Did you make the wooding of the arcades of your pictures yourself?
« Last Edit: September 20, 2018, 10:55:40 am by gambaman »

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Re: 15.7KHz composite sync generator
« Reply #20 on: September 20, 2018, 03:12:34 pm »
I just dropped 96$ on a jrok rgb to component board

I have looked at it and it requires a 15KHz composite sync signal as well as the red, green and blue signals. I think you can connect the red, green and blue signals directly to your VGA and use my design to generate the composite sync signal. I have read that the jamma maximun Csync voltage is 5V so I would use a voltage divider at the output of the PIC just in case. A pair of 1K ohm series resistor should be OK. Place them like this:


Note that you will have to configure the VGA for a frequency of 15.7Khz.

for most things console emulation i'd be using a raspberry pi with the GERTVGA board and that allows you to out put 15khz.

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Re: 15.7KHz composite sync generator
« Reply #21 on: September 20, 2018, 03:16:40 pm »

I'd be very interested to know what modern video cards (if any) support component out, but information is very scarce.



I think you have the ATI cards list correct from my memory.
Also, Nvidia 8400,9400, 9700 era video cards while not powerful gaming devices do output component via their 9 pin round connector with the proper cable.
I have a few and tested them all a few yrs ago on component TV's.
only 480i I think though.
looked really good.

Zebidee

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Re: 15.7KHz composite sync generator
« Reply #22 on: September 20, 2018, 03:39:58 pm »
If they are going to be used to carry a composite video signal then it is 1V, but according to the official CENELEC standard EN 50049-1:
"When the signal on this terminal is exclusively a synchronization signal, the peak to peak voltage is 0,3 V (23 dB, +10 dB)"

Makes sense yet still seems low, esp when everywhere else it talks about 1v for sync, and I don't know what "Superimposed d.c. component within 0 V and +2 V" means. But hey, if that's all/what it needs then great.

Quote
P.D: Did you make the wooding of the arcades of your pictures yourself?

The ones in my sig line are mostly restored from gutted shells of old arcade cabs, usually no monitor and no proper control panels even, except for the astro/candy and Wonder Boy cabs. I've done a lot more that aren't in those pics.

At first I did couple of cabs for myself, paying attention to how they look as much as how they functioned. Started incorporating non-arcade things like a simple jukebox and PC games. Removed coin mechs and installed custom admin panels with volume controls and USB/audio ports to make them more home-friendly. Surface restoration to remove/repair damage. Custom art, not overdone, restored original art where possible. Attention to details. CRTs all the way.

Then friends would see them, play, and want one for themselves, mates rates accepted. More cabs done. Word of mouth, more people, better offers were made, and I did cabs for them too.

Some of the cabs "shells" I got for free, but were like junk. Full of rat sh!t, rotting from rat piss, no monitor, no control panel, scratched and ripped to hell... and I restored them (inside and out) and eventually sold them for tidy sums. Oddly, it is these ones I miss the most.

I'm lucky because in addition to being a computer nerd, I spent much of my youth hanging around in art workshops and soaked up a few things about restoration & tools. I can manipulate wood and other materials, but I'm an artist more than a carpenter.

I had to move countries a few years ago and had to downsize all my arcade and other stuff, which is also why I took a break for other things and only have 2 cabs right at the present time. (Working on more projects now!).
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Zebidee

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Re: 15.7KHz composite sync generator
« Reply #23 on: September 20, 2018, 03:51:24 pm »
I think you have the ATI cards list correct from my memory.
Also, Nvidia 8400,9400, 9700 era video cards while not powerful gaming devices do output component via their 9 pin round connector with the proper cable.
I have a few and tested them all a few yrs ago on component TV's.
only 480i I think though.
looked really good.

Be interesting to know if they can be coaxed to do component via their DVI/VGA heads, and thence to accept other modes as well. The ATIs have the same 480i issue with the round "s-video" connector, which looks OK for windows and some games but is pretty limiting for arcade stuff tbh.
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Re: 15.7KHz composite sync generator
« Reply #24 on: September 20, 2018, 03:57:55 pm »
I think you have the ATI cards list correct from my memory.
Also, Nvidia 8400,9400, 9700 era video cards while not powerful gaming devices do output component via their 9 pin round connector with the proper cable.
I have a few and tested them all a few yrs ago on component TV's.
only 480i I think though.
looked really good.

Be interesting to know if they can be coaxed to do component via their DVI/VGA heads, and thence to accept other modes as well. The ATIs have the same 480i issue with the round "s-video" connector, which looks OK for windows and some games but is pretty limiting for arcade stuff tbh.

8400 GS works with soft 15khz.
http://forum.arcadecontrols.com/index.php?topic=120379.0
But i'm not sure if the component out will do it.
However the component out on those cards list HD resolutions over the component so maybe.
« Last Edit: September 20, 2018, 03:59:55 pm by nitrogen_widget »

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Re: 15.7KHz composite sync generator
« Reply #25 on: September 20, 2018, 04:14:57 pm »
If/when I get my hands on a component input SDTV I'll see what I can do. I can see that there may need to be a new thread on getting component to work, hopefully including a DIY converter circuit.
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Re: 15.7KHz composite sync generator
« Reply #26 on: September 20, 2018, 08:46:10 pm »
The latest schematic i have is this one, and IT IS NOT COMPLETE. It's done By Bo Thompson, but he mentioned a few weeks back that some of the resistors aren't right. I've messaged him so hopefully he can clear that up. Should be good to order parts from though, and mb change/add some extra resistors later. And i think the C4 cap might have the polarity wrong, because the straight bar is +ve - might be why he's blown a few up?

Schematic removed, see updated version is my next post below.
« Last Edit: September 24, 2018, 05:36:52 am by buttersoft »

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Re: 15.7KHz composite sync generator
« Reply #27 on: September 20, 2018, 11:56:54 pm »
Thanks Buttersoft (and Bo)

I have too many questions about this schematic, my circuit design skillz are not good enough to work it out myself. Maybe Gambaman can have a look.

Hmmm, yes, C4 seems to be back-to-front. Same with C1, C2 & C3? The curved part is negative, should be towards ground/signal direction.

R13, R17, R18 on the RGB inputs look like they are resistors, but drawn like a transistor with a base... what exactly are they?

Transistors Q1,Q2,Q3 (labels are misplaced) I guess are there to amplify the signal (or a switch?) - seems to be missing something. Resistor on the Vcc/collector inputs? Are the Y,Pb,Pr inputs to the base going to be high enough for them to turn on? (there is a base/emitter voltage drop of ~0.7v yes?). Also worried about what damage might result if a transistor failed, there is no protection built in.

Why add 5V/Vcc to sync input over that resistor R7? Also, why connect Vcc to ground there (via the backwards C4?).

Sorry if my questions seem dumb, it's a better design than anything I could come up with.

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Re: 15.7KHz composite sync generator
« Reply #28 on: September 24, 2018, 05:42:01 am »
Bo sent me an updated schematic. I added a few notes, but haven't had time to go over the schematic in detail. C5, C6, and C7 are oriented right though, you want the +ve leg pointing toward your source, -ve to the TV.


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Re: 15.7KHz composite sync generator
« Reply #29 on: September 25, 2018, 03:05:08 pm »
Sync on Green is a standard used for SCART input, but I've never come across a SCART TV that demands this in preference to full RGBS.

SoG is different to component (YPbPr) in that the green "chroma" is still present on the G line (TV must know how to separate it out). With component, the "Y" (green wire) carries just luma (brightness) & sync, no green. The green is not actually present at all, and green is determined by the TV using simple calculus/algebra as it already knows blue (-luma) and red (-luma) & luma.

I'd be very interested to see if someone can work out how to build a simple DIY VGA/DVI-component conversion circuit. My electronics skills aren't good enough (yet) to design such a circuit, but I could build one. There would be an awful lot of retrogaming people interested in building it.

I've also been looking at how to get component out of a PC *without* needing a converter. Some video cards support component out, but it is designed for HDTVs and video projectors that can display VGA/~31khz modes normally output by PCs like 480p, 720p and 1080p. The reason for providing this support is that these HDTVs and projectors were used a lot in business (presentations etc) and home theatre applications, but this is less common now. For us, a problem arises because SDTVs (which we prefer for retrogaming) that accept component inputs cannot display these modes.

Another problem is that it is difficult to work out just which video cards support component out in the first place. Mostly it seems to be older cards, I have no idea about newer cards. There are some NVIDIA cards that support component, but a lot more ATI/AMD cards seem to. In particular, cards with VIVO support seem to be component-capable. For example, AFAIK these old ATI cards support component out:

    ATI RADEON 9800 Series
    ATI RADEON 9700 Series
    ATI RADEON 9600 Series
    ATI RADEON 9500 Series
    ATI RADEON 8500 Series
    ATI RADEON 8500LE Series
    ATI ALL-IN-WONDER RADEON 9800 Series
    ATI ALL-IN-WONDER RADEON 9700 Series
    ATI ALL-IN-WONDER RADEON 9600 Series
    ATI ALL-IN-WONDER RADEON 8500
    ATI ALL-IN-WONDER RADEON 8500DV

I'd be very interested to know what modern video cards (if any) support component out, but information is very scarce.

Who cares if you can't produce an image on component SDTV? Well, you can. If your card is capable of outputting component video you are already halfway there, you just need to use another application like Powerstrip, CRT_emudriver or soft15khz to generate the 15khz modes. I've done this before with Powerstrip (long time ago) & a Radeon 9600 (iirc), but I see no clear reason why CRTEMU and soft15khz would not work like this as well. Note that these apps don't actually modify the video signal at all, they just generate modes for your card to output. Your video card does all the signal conversion for you already, if able to and configured properly.

Component video output from a compatible card will be available on the RGB signal outputs, you just need to add in ground and hack your VGA/DVI output to 3 RCA female connectors (or RCA/component cables with these male connectors on the other end). You can buy cheap, passive adapters on ebay etc for about $3. Or you can just build your own (AFAICT, all you'd need to patch through is RGB, ground. Sync is already on green). You might like to keep wires for VGA pins 11, 12 & 15 available (as these are used for monitor EDID info, which may (or may not) be needed by your video card).
https://www.ebay.com/itm/3-RCA-RGB-Video-Maschio-a-HD-15-Pin-VGA-Component-Video-Jack-Adattatore-Nero/282709683678?hash=item41d2cf6dde:g:nXoAAOSwWLBZ8rb~

Why not just buy an overpriced VGA-component converter? Well, if you like, I'm a cheapskate and don't understand why you have to buy new expensive stuff to play old games (which is the default advice I keep on hearing on these forums) when there are cheaper, possibly better options. Building it is probably easier. Plus it can be hard and expensive for me to get specialised electronic stuff where I am (rural Thailand). Out of the last 3 shipments of electronic stuff from overseas, customs intercepted 2 of them, charged me more in tax/bribes and caused delays/concerns from my suppliers. It is a PITA. However, this VGA-component converter does look attractive and is getting close to the right price range:
https://www.monoprice.com/product?p_id=8668

ATM, I don't even have a component input TV to test my theories on, but I do have a bunch of old video cards. I was stimulated to look into this recently by another poster who is from Columbia, who faces much worse problems than I do with getting stuff like VGA-component converters from overseas.

PS - you don't I don't think that you need a voltage divider on the 5v sync, but maybe it won't hurt. I've done heaps of SCART cables without needing to pull sync voltage down, had good results, and when I've tried using voltage dividers on sync it didn't help/caused problems so I removed it. Maybe I missed something.

EDIT - italics on the PS, last bit

PPS - If doing a voltage divider on sync, don't forget that video signals are normally 75 ohm terminated at the TV/monitor.

I have a JROK color space converter board that can convert RGB to component and SVideo without changing the resolution. It works ok if you buy or build decent shielded and properly grounded cables.

Scart and DB15 connectors are not a color space or a sync standard. They are just plugs that can be wired for a variety of signals. A scart plug can be wired for SVideo, component, RGBS, RGsB etc. some scart TVs can't display RGB at all. Similarly, the "vga" port (db15) on my arcade monitor accepts both RGBHV and RGBS.

Buy an Extron RGB interface off eBay. They are cheap and can convert any rgb sync type to any RGB sync type. It can also give you a clean signal which will work better with a JROK color space converter. Should cover all bases for using an American SD crt tv for mame through component.


Zebidee

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Re: 15.7KHz composite sync generator
« Reply #30 on: September 25, 2018, 09:59:41 pm »
I have a JROK color space converter board that can convert RGB to component and SVideo without changing the resolution. It works ok if you buy or build decent shielded and properly grounded cables.

Naturally, you want decent cables. Note that $5 on cheaper (but decent) cables is usually going to give you the same quality as $50 gold-plated shielded cables unless you are running them over long distance through lot of interference. Shielded cables for component are good as there is no "redundancy" built into the standard, so any degradation is going to be more apparent.

Quote
Scart and DB15 connectors are not a color space or a sync standard. They are just plugs that can be wired for a variety of signals. A scart plug can be wired for SVideo, component, RGBS, RGsB etc.

That is correct and also obvious, I'm not sure why you raise it. When I mentioned Sync on Green (SoG or RGsB) in relation to SCART earlier, I meant that the pinout was "standardised", so that you know which pins to connect for what. None of this means that your particular TV can actually do anything with RGsB video inputs.

Quote
some scart TVs can't display RGB at all.

True, again I don't know why you raise this. They are quite rare, but there are some really cheap/nasty SCART TVs can't do RGB. I've found exactly one SCART TV like this out of the countless ones I've tested. Once I travelled 4 hours to get a 20inch "Goldstar" brand SCART TV, only to find after some experimentation that it didn't take RGB at all - only displayed an image with composite video inputs. Avoid "Goldstar" and similar "Sh!t" brand SCART TVs.

Quote
Buy an Extron RGB interface off eBay. They are cheap and can convert any rgb sync type to any RGB sync type. It can also give you a clean signal which will work better with a JROK color space converter. Should cover all bases for using an American SD crt tv for mame through component.

The Extron RGB 192 (and similar) are not quite cheap at $40, although I do see a lot of 2nd hand ones being sold on ebay from US for about $20-30 (which makes you wonder why they are being re-sold). Although it is a nice bit of kit to have on hand, it is not essential. It does give consistency of RGB video signals as inputs for the JROK, but note that the JROK comes with pots to adjust the component video output signals to help account for variations with either video inputs or with individual TVs.

The JROK encoder costs another $80 on top of all that. Nice gear, yet $30 would be a better price, at least for the component-only version of this item (judging from the electronic components). Would love to see a circuit diagram for it and then maybe compare/build it for even less. It could probably also improved upon by putting in a sync conversion circuit like gambaman's.

The gear looks good but it costs too much. If you are willing to spend $120 + shipping from US then go for it and get the Extron RGB + JROK.
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Zebidee

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Re: 15.7KHz composite sync generator
« Reply #31 on: September 25, 2018, 10:07:25 pm »
Check out this thread from the Sega forums on RGB to Component. This is Ace's design and discussion/variations to it:

http://www.sega-16.com/forum/showthread.php?22237-New-RGB-to-Component-converter-design-using-the-BA7230LS

Ace's base design v5.0, using the BA2730LS chip for RGB-YUV conversion and LM1881 for sync, attached.



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