VGA2SCART and VGA2NTSC - RGBS, S-Video and Composite output

[Gunstar]

Mike Chi has released a VGA2SCART board that is open source and is available now on OSH Park here


A redesigned version which also outputs S-Video and Composite is on the way


The VGA2SCART is powered from the VGA/DB15 pin 9 whilst it looks like the VGA2NTSC will be powered via micro USB input.

[fernan1234]

I like the VGA2NTSC. That's something that's been completely lacking all along up to this time. I'd personally do without the silly SCART out connector for RGBS output, and instead just use another DE15 connector that can then be used with a BNC or SCART adapter if needed.

Hopefully "VGA" there doesn't only mean RGBHV from something like the MiSTer, but can also convert any RGBS (regardless of sync being tapped from composite video, luma, or just clean sync) sources to NTSC.

[nmalinoski]

Hopefully "VGA" there doesn't only mean RGBHV from something like the MiSTer, but can also convert any RGBS (regardless of sync being tapped from composite video, luma, or just clean sync) sources to NTSC.

I agree; I think its utility would be greater if it was able to take both TTL and 75Ohm syncs, but I'm not sure how feasible that is. What little video equipment I've seen that will take both RGBHV and RGBS usually expects TTL composite sync, or has a switch to allow accommodation of 75Ohm sync.

[Guspaz]

I think SCART makes more sense here, for several reasons:

1) Most users probably have a SCART-based setup, so one less adapters in the chain is preferable. SCART-to-SCART on the output is far more likely than RGBS DE-15-to-DE-15. If you're always going to need an adapter with a DE-15 output, you might as well make the connector something that might be used without adapters.

2) The original purpose of the board was to adapt from VGA to SCART, a VGA-to-DE-15 adapter that does nothing but changes RGBHV to RGBS isn't needed, there are many cheap extron converters that do that on ebay

3) DE-15 output with RGBS with 75ohm sync is kind of confusing/nonstandard

4) If custom adapters are needed, it's much easier to open up a SCART connector and rewire it than it is a DE-15, or even solder directly to the VGA2NTSC PCB if you're getting fancy.

[Josh128]

Fantastic Mike. So would this work with systems like the Dreamcast to get VGA out in 15KHz in games that support it? Would it not be possible to make it compatible with 31KHz also? What about component out?

Basically you'd have a replacement for the AA 9a60 if you did that.

[fernan1234]

Really hoping RGBS 15khz from consoles to composite & S-video ends up happening. I have a full RGB setup for almost a dozen systems, but sometimes I irrationally feel it would be cool to play around with some content downgraded to s-video or even composite. Sounds like Mike would like at least some systems the MiSTer emulates to have a composite video look, so I guess I'm not the only one with that kind of urge.

This would make it possible to just throw the VGA2NTSC into an RGB chain when the mood for inferior but nostalgic video quality hits you, without needing to swap around cables for each system. Or, more practically, this would let you integrate a consumer NTSC TV easily into an RGB setup.

[Gunstar]

VGA2NTSC has been released: https://www.retrotink.com/post/vga2ntsc-released

Notes

The encoder is based on the AD725. You must use negative going sync pulses for this to work. If your source is RGBs, then either disconnect the vertical sync line (it's pulled high internally) or set the vertical sync line to high. On the MiSTer, don't use composite sync = 1 unless you disconnect the vertical sync line, as it is normally held low.


The board is hardwired to output NTSC. Building a PAL version is possible by switching the crystal to the appropriate frequency and setting the mode pin on the AD725 encoder.


The one thing I'm not 100% happy with the design is the generation of the NTSC encoder clock. Unfortunately, it would require a complex circuit to multiply the horizontal frequency up to produce a phase locked chroma clock. So in this design, the 3.58 MHz carrier is not synchronized to the origin video clock resulting in more color fringe artifacts. However, this does not affect S-Video quality.


The sync line for the SCART is derived from the composite video signal and output as standard 75 ohm video. No TTL CSYNC nonsense here.


There is no scaling - you'll need to feed it 15 kHz sources.

[Bratwurst]

Anyone looking to have some of these made? I could go for a kit of parts to assemble myself.

[pcb_revival]

Is the VGA2SCART a competing product to the ArcageForge Ultimate Scart Adapter or something else?

[fernan1234]

Anyone looking to have some of these made? I could go for a kit of parts to assemble myself.

If you or anyone else decide to assemble a spare one let me know and I'll buy it at a worthwhile price (VGA2NTSC)

[BazookaBen]

So guys, I'm lost.

What type of setup is the VGA2Scart designed for? Like what devices are outputting 15kHz with separate sync that need to be combined? CRT Emudriver can output c-sync, so that seems to not be what this is aimed at.

[bonzo.bits]

So guys, I'm lost.

What type of setup is the VGA2Scart designed for? Like what devices are outputting 15kHz with separate sync that need to be combined? CRT Emudriver can output c-sync, so that seems to not be what this is aimed at.

I need to get from VGA to SCART, this might be too expensive of a solution though. Given the HDMI out from the MiSTer already requires a HDMI to VGA converter, so maybe a VGA to RGB cable would be more economical.

[fernan1234]

I need to get from VGA to SCART, this might be too expensive of a solution though. Given the HDMI out from the MiSTer already requires a HDMI to VGA converter, so maybe a VGA to RGB cable would be more economical.

Adequate HDMI to VGA converters are so cheap already, even if you build one of these yourself it won't be as cheap probably. Though if you want to use a pro CRT monitor or TV with SCART, then you need to pair such adapters with a sync combiner device. This VGA2SCART does both things for you.

[Bratwurst]

So guys, I'm lost.

What type of setup is the VGA2Scart designed for? Like what devices are outputting 15kHz with separate sync that need to be combined? CRT Emudriver can output c-sync, so that seems to not be what this is aimed at.

I have s-video only sets that cannot be modded for RGB input, and though I already have a conversion board it's an old design and I'd like to see the output quality of this. So this appeals to me, I'm just not curious enough to pay $50 to get a board made through Oshpark. Will have to look at a bulk production through another PCB manufacturer, anyone have suggestions?

[Gunstar]

Mike said the VGA2SCART will spit out 31khz RGBs too from a 31khz RGBHV source. That would be handy for OSSC users wanting to use the full LPF abilities via the SCART input for VGA sources I believe.

GBS Control also needs sync combined/taken down to 75ohm for people looking to use the 240p downscale feature with a consumer crt, it should be cheaper to make than an UMSA looking at the fewer assembly parts. I do wonder how it compares to the UMSA in terms of quality, the "color fringe artifacts" mentioned by Mike sounds like it might not be as good?

@Bratwurst - I've used JLCPCB a couple of times without issue. I think Corona has sent up prices of hobby PCB manufacturing but it should be cheaper than OSH which seems to have gotten really expensive these last few months

[kitty666cats]

Gonna be a really good year for 'VGA' (and/or DE-15) + SCART devices! More cool shit coming down the pipeline soon, and I can't wait to try as much of it as possible hehe.

Friendly reminder not to sleep on Insurrection Industries' SCART2DVI, with a simple DVI-I or DVI-A to DE-15 dongle the thing essentially becomes a more modern Sync Strike with the bonus of being able to switch on/off the sync stripper (plus an LPF). Makes for VERY easy access to Extron RGB interfaces! I was also quite happy to recently find that the Optoma SCART switch/splitter dongle I bought is good for 15kHZ RGB via DE-15!

Even MORE stuff should be coming eventutally, if my (sometimes unreliable) memory is serving me right. I should not elaborate, but if I'm indeed correct then it's gonna be one heck of a cool & long-overdue device :3

I still kick myself for never getting one of those female SCART to DE-15 + audio cables that RGC UK used to make, then mysteriously stopped making without much of an explanation

~~~~~~~~~~~~~~~~~~~~~~~

Tangentially related:

Any of you guys ever pick one of these cables up? And, if so, have any of you found a 9 pin to 15 pin adapter or cable that works with it, pinout-wise?

https://www.ebay.com/itm/PHILIPS-CM8833 ... 0754731999

[kitty666cats]

Anyone looking to have some of these made? I could go for a kit of parts to assemble myself.

If I'm not mis-reading you, and you plan to assemble/sell some of your own, I could be interested! I would also VERY gladly pay someone to put together a GBS8200 w/ the Wi-Fi board and all the other suggested physical mods. I have a late 2019 model GBS8200, a Pi, and the necessary Wi-Fi board already... just antsy about trying to set it all up and most likely end up botching it :p

[Bratwurst]

If I'm not mis-reading you, and you plan to assemble/sell some of your own, I could be interested! I would also VERY gladly pay someone to put together a GBS8200 w/ the Wi-Fi board and all the other suggested physical mods. I have a late 2010 model GBS8200, a Pi, and the necessary Wi-Fi board already... just antsy about trying to set it all up and most likely end up botching it :p

I was hoping someone else had been considering pulling together an order of the necessary components and I'd parasitize a set of parts off of them, but JLCPCB as recommended by Gunstar is quoting much better rates than Oshpark so, maybe. $2 + shipping for 5 boards, $5 + shipping for 10, etc. So I'll consider it- I want to see if I can order everything else from Mouser or Digikey without having to source too many things from a dozen different vendors.

Having one assembled and on hand would allow me to design and fab a 3D printed enclosure too.

Only thing I dislike about the design is the miniaturized USB port for power, they're never fun to solder in and they're not durable.

[mikechi2]

Hi Guys - thanks for the interest! Just a quick PSA: I have reasonable expectation that the VGA2NTSC will at least work since I built a copy and tried it but I have not built out the VGA2SCART yet.

[Bratwurst]

Hi Guys - thanks for the interest! Just a quick PSA: I have reasonable expectation that the VGA2NTSC will at least work since I built a copy and tried it but I have not built out the VGA2SCART yet.

I just skimmed over the BOM, do you have a link to the AliExpress vendor you sourced the scart connector from? Presuming that you got it from AliExpress.

EDIT: BTW, thank you for designing this and opening it up to the public.

[mikechi2]

Here you go: https://console5.com/store/female-scart ... angle.html
Yet another reason why I detest SCART -- random ass parts sourcing.

And you're very welcome!!

[fernan1234]

Here you go: https://console5.com/store/female-scart ... angle.html
Yet another reason why I detest SCART -- random ass parts sourcing.

And you're very welcome!!

This is why you and other important producers should stick with a superior and convenient DSub-15 port--let the consumer who wants to stay with old SHART to deal with adapters. Nowadays, for people who can't make their own cable, it's basically the same cost to order good quality SCART cables vs. custom Dsub15 cables, anyway.

And another thank you for all you do!

[bonzo.bits]

Adequate HDMI to VGA converters are so cheap already, even if you build one of these yourself it won't be as cheap probably. Though if you want to use a pro CRT monitor or TV with SCART, then you need to pair such adapters with a sync combiner device. This VGA2SCART does both things for you.

I'm using a MiSTer which has an option to output composite sync on the H sync line. Although I do have a DC on the way so this thing sounds good for hooking both up to a CRT.

I was hoping someone else had been considering pulling together an order of the necessary components and I'd parasitize a set of parts off of them, but JLCPCB as recommended by Gunstar is quoting much better rates than Oshpark so, maybe. $2 + shipping for 5 boards, $5 + shipping for 10, etc. So I'll consider it- I want to see if I can order everything else from Mouser or Digikey without having to source too many things from a dozen different vendors.

Having one assembled and on hand would allow me to design and fab a 3D printed enclosure too.

Only thing I dislike about the design is the miniaturized USB port for power, they're never fun to solder in and they're not durable.

I would also parasatise if someone is looking at having some PCBs made up.

[BuckoA51]

VGA2SCART could do with optional power connector to provide blanking/rgb up voltages on TVs that need them.

[strayan]

Gonna be a really good year for 'VGA' (and/or DE-15) + SCART devices! More cool shit coming down the pipeline soon, and I can't wait to try as much of it as possible hehe.

Friendly reminder not to sleep on Insurrection Industries' SCART2DVI, with a simple DVI-I or DVI-A to DE-15 dongle the thing essentially becomes a more modern Sync Strike with the bonus of being able to switch on/off the sync stripper (plus an LPF). Makes for VERY easy access to Extron RGB interfaces! I was also quite happy to recently find that the Optoma SCART switch/splitter dongle I bought is good for 15kHZ RGB via DE-15!

Even MORE stuff should be coming eventutally, if my (sometimes unreliable) memory is serving me right. I should not elaborate, but if I'm indeed correct then it's gonna be one heck of a cool & long-overdue device :3

I still kick myself for never getting one of those female SCART to DE-15 + audio cables that RGC UK used to make, then mysteriously stopped making without much of an explanation

~~~~~~~~~~~~~~~~~~~~~~~

Tangentially related:

Any of you guys ever pick one of these cables up? And, if so, have any of you found a 9 pin to 15 pin adapter or cable that works with it, pinout-wise?

https://www.ebay.com/itm/PHILIPS-CM8833 ... 0754731999

[timg]https://i.ebayimg.com/images/g/Pp0AAOxy ... -l1600.jpg[/timg]

Pinout looks the same:
https://www.amazon.com/CGA-9-Pin-15-Pin ... e=UTF8&me=

CM8833 pinout http://www.ym2149.com/philips_pinout.jpg

[mikechi2]

VGA2SCART could do with optional power connector to provide blanking/rgb up voltages on TVs that need them.

Yeah that and I'm going to try and see if I can get a power harvester circuit (from the sync lines) working before I officially post the entire design for the VGA2SCART

[unmaker]

I wanted one of each for myself so I ordered some PCB's from JLCPCB. You can order only in multiples of 5 so I ordered 5 VGA2SCART's and 20 VGA2NTSC's for those who may be interested in buying an assembled board.

[kitty666cats]

Gonna be a really good year for 'VGA' (and/or DE-15) + SCART devices! More cool shit coming down the pipeline soon, and I can't wait to try as much of it as possible hehe.

Friendly reminder not to sleep on Insurrection Industries' SCART2DVI, with a simple DVI-I or DVI-A to DE-15 dongle the thing essentially becomes a more modern Sync Strike with the bonus of being able to switch on/off the sync stripper (plus an LPF). Makes for VERY easy access to Extron RGB interfaces! I was also quite happy to recently find that the Optoma SCART switch/splitter dongle I bought is good for 15kHZ RGB via DE-15!

Even MORE stuff should be coming eventutally, if my (sometimes unreliable) memory is serving me right. I should not elaborate, but if I'm indeed correct then it's gonna be one heck of a cool & long-overdue device :3

I still kick myself for never getting one of those female SCART to DE-15 + audio cables that RGC UK used to make, then mysteriously stopped making without much of an explanation

~~~~~~~~~~~~~~~~~~~~~~~

Tangentially related:

Any of you guys ever pick one of these cables up? And, if so, have any of you found a 9 pin to 15 pin adapter or cable that works with it, pinout-wise?

https://www.ebay.com/itm/PHILIPS-CM8833 ... 0754731999

[timg]https://i.ebayimg.com/images/g/Pp0AAOxy ... -l1600.jpg[/timg]

Pinout looks the same:
https://www.amazon.com/CGA-9-Pin-15-Pin ... e=UTF8&me=

CM8833 pinout http://www.ym2149.com/philips_pinout.jpg

A buddy on Discord said that setup would be almost right, except would be missing sync somewhere?

I know they're not crazy hard to build, but ahh I wish there was someone who sold a female SCART to 15kHz DE-15 + audio breakout CABLE! Something for, like, easy access to Extron stuff or other various processors / DIY connectors for RGB modded CRTs.

As I said I've already got a SCART2DVI (Which rules! Switchable sync stripper and LPF can't hurt to have. Can you switch off the stripper on Sync Strikes? I forget ) and other ways to make the SCART>DE-15 connection, but one single widely available ~ sleek ~ looking cable would be rad to have around! Much props to the PCBs / little boxes we already have, they're super great, I just like sexy cables

Do we know why the RGCUK one disappeared in kinda a mysterious manner?

:shrug: It's all no biggie to me though! I'm just a goober who always loves picking up cool looking cables / AV devices

[Bratwurst]

I wanted one of each for myself so I ordered some PCB's from JLCPCB. You can order only in multiples of 5 so I ordered 5 VGA2SCART's and 20 VGA2NTSC's for those who may be interested in buying an assembled board.

I'd be interested in one of those VGA2NTSC pcbs and the parts if you've ordered those and are up to letting them go without putting them together, since I can do that myself.

[unmaker]

I wanted one of each for myself so I ordered some PCB's from JLCPCB. You can order only in multiples of 5 so I ordered 5 VGA2SCART's and 20 VGA2NTSC's for those who may be interested in buying an assembled board.

I'd be interested in one of those VGA2NTSC pcbs and the parts if you've ordered those and are up to letting them go without putting them together, since I can do that myself.

No problem. That's fine with me.