Sidequest: VGA scan doubler

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exxos
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Re: Sidequest: VGA scan doubler

Post by exxos »

Happy to help. I don't think many realise how important these types of video mods are yet even. With RF basically dead and scart pretty much gone, HDMI is the only way forward to keep the ST's connected to a modern screen. I'm sure once the ball starts rolling people will be flooding to towards the things!
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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Smonson
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Re: Sidequest: VGA scan doubler

Post by Smonson »

I've just sent off the boards order for prototype version 2 of this mod, so keep your fingers crossed for me! 8-)
scandoubler2.png
scandoubler2.png (244.1 KiB) Viewed 5518 times
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exxos
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Re: Sidequest: VGA scan doubler

Post by exxos »

Smonson wrote: Sat Apr 18, 2020 1:59 pm I've just sent off the boards order for prototype version 2 of this mod, so keep your fingers crossed for me! 8-)

:bravo: :coolpics:
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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Icky
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Re: Sidequest: VGA scan doubler

Post by Icky »

:thumbup: - nice board. Looking forward to seeing it working.
troed
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Re: Sidequest: VGA scan doubler

Post by troed »

exxos wrote: Mon Apr 08, 2019 2:17 pm I'm sure once the ball starts rolling people will be flooding to towards the things!
Yeah ... about one board, at least, per every active ST user today. It's a game changer.

/Troed
beel1
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Re: Sidequest: VGA scan doubler

Post by beel1 »

Out of curiosity are there enough free IOs on the V2 to handle a 4th bit per channel? (for STEs, even if I know that instead of piggybacking the Shifter, that would require to solder everything from the mainboard) :D
I think that needs 12 more IOs I guess?

Anyway that's a really nice work :bravo:
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Smonson
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Re: Sidequest: VGA scan doubler

Post by Smonson »

Thanks beel1.
beel1 wrote: Sun Apr 19, 2020 3:34 pm Out of curiosity are there enough free IOs on the V2 to handle a 4th bit per channel? (for STEs, even if I know that instead of piggybacking the Shifter, that would require to solder everything from the mainboard) :D
Probably, but I didn't wire it up that way. The RAMs are 16 bits wide, so I guess that means (3 colours * 2 RAMs) plus the IO in from the shifter and out to VGA = 12 extra IOs. Can always go up from the TQFP100 to the 144 version of the chip if necessary - I reckon it could fit :)
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Smonson
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Re: Sidequest: VGA scan doubler

Post by Smonson »

I put the first of these new boards together today, and got a good result out of it:
sc2-3.jpg
sc2-3.jpg (267.18 KiB) Viewed 5365 times
sc2-1.png
sc2-1.png (1.79 MiB) Viewed 5365 times
(excuse the moire effect, it's just the effect this TV has on my phone camera)
sc2-2.png
sc2-2.png (1.66 MiB) Viewed 5365 times
There's a bit of analogue noise in the picture, but I suspect that is probably a combination of my bargain-basement VGA cable, dodgy hand-made ungrounded IDC pin header adapter, and the fact that this is a cheap TV and not a monitor. I also haven't done a proper video "porch" - it's just dropping to to the normal black point around the horizontal sync, which is good enough for the purposes of a prototype.

These pics are at 50Hz, haven't made it work for 60Hz yet. Still - it's promising. The picture is nice and steady. I'm content with it!
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exxos
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Re: Sidequest: VGA scan doubler

Post by exxos »

Nice one! :cheers:
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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JezC
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Re: Sidequest: VGA scan doubler

Post by JezC »

Looks like some great progress on this!
:thumbup: :goodpost: :bravo:
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