upscaler core via serial?

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Newsdee
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upscaler core via serial?

Postby Newsdee » Mon Jan 13, 2020 10:17 am

This is just an idea... but would it be possible to turn MiSTer into a generic upscaler via the serial port?

It will need an ADC, which I suspect may not be cheap...
but if doable, it would allow connecting legacy devices to a MiSTer to reuse the standard upscaler, scanlines, and gamma options.

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Re: upscaler core via serial?

Postby crocky » Mon Jan 13, 2020 12:48 pm

Love this idea, scalers on MiSTer are amazing.

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Re: upscaler core via serial?

Postby Dacide » Mon Jan 13, 2020 1:09 pm

I was thinking something similar, like a kind of supergun for arcade boards with USB controllers.
A new I/o board with level shifters for digital inputs and ADC for analog video.

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Re: upscaler core via serial?

Postby Sorgelig » Mon Jan 13, 2020 4:56 pm

For analog video input it's important to detect the pixel clock properly which is not trivial job. This is main problem of generic stand-alone scaler implementation. Cores provide explicit pixel clock to the scaler, so such problem doesn't exist.
And of course high quality high frequency ADC will be required. For serial input, with separate signal per color, then it will require 8 times (at least) higher clock than maximum possible pixel clock. For 15KHz the pixel clock can go up to ~14MHz, so it will require about 112MHz for serial ADC data transmission. For external input such frequency is not easy to make stable.
I even not talking about complexity of external ADC board which probably will need another small FPGA.

Better to have a separate de10-nano for such purpose where 40 pin connector can be used for special input board where normal parallel ADC will be used. There is no reason to use exactly MiSTer project for this.
So the problem of pixel clock detection is still exists. Actually can use some existing integrated video digitizer chip similar to the one used in OSSC, so it will detect the pixel clock. AFAIK such integrated chips have usual problems with video signals as they expect some more or less standard video parameters.

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Re: upscaler core via serial?

Postby orange808 » Mon Jan 13, 2020 4:58 pm

In theory, a device based on the MiSTer scaler code could become a very powerful video processor.

It might even find an audience among video professionals as well.

Don't know if the current MiSTer hardware can do it, though.

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Re: upscaler core via serial?

Postby Newsdee » Tue Jan 14, 2020 2:56 am

Thanks for the replies! I thought I may have been missing something, otherwise I suppose somebody may have done it already.

Just for my understanding, I thought the serial connection exposed 7 pins, so wouldn't that be enough for RGB+Sync (+ ground)?
Or do they all require separate ground? (which seems to be the case in the VGA 15-pin connector)

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Re: upscaler core via serial?

Postby Sorgelig » Wed Jan 15, 2020 3:04 pm

Newsdee wrote:Just for my understanding, I thought the serial connection exposed 7 pins, so wouldn't that be enough for RGB+Sync (+ ground)?
Or do they all require separate ground? (which seems to be the case in the VGA 15-pin connector)

They are digital, not analog.

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Re: upscaler core via serial?

Postby BigMac740p » Mon Jan 20, 2020 2:56 pm

Good news, Smoke Monster has announced that the guy behind the OSSC is planing an addons board for the DE10-Nano to transform it into a OSSC Pro Scaler.

Ref: https://shmups.system11.org/viewtopic.php?f=6&t=65892

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Re: upscaler core via serial?

Postby Newsdee » Tue Jan 21, 2020 3:56 am

The FPGA seems different. Unless he is planning two versions?

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Re: upscaler core via serial?

Postby BigMac740p » Tue Jan 21, 2020 2:01 pm

Newsdee wrote:The FPGA seems different. Unless he is planning two versions?


What you means? The original OSSC as his own board design but a De10-Nano add-ons is planned.

From the developer page: "For DIY-builders and those who can't wait for the final HW, a small add-on PCB compatible with a couple Terasic FPGA dev boards (DE10-Nano, DE2-115) is in works and available soon"

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Re: upscaler core via serial?

Postby Newsdee » Tue Jan 21, 2020 3:44 pm

Ah, so that means there will be two versions... Basically, one small add-in board to plug to either a DE10-Nano or/and a DE2-115, and separately (later), a full board for a "standalone" version. Some people talked of this being consolized to get MiSTer cores, but I hope they can collaborate to bring the core to MiSTer instead (even if it means using their custom board instead of an IO board).

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Re: upscaler core via serial?

Postby BigMac740p » Tue Jan 21, 2020 3:50 pm

Newsdee wrote:Ah, so that means there will be two versions... Basically, one small add-in board to plug to either a DE10-Nano or/and a DE2-115, and separately (later), a full board for a "standalone" version. Some people talked of this being consolized to get MiSTer cores, but I hope they can collaborate to bring the core to MiSTer instead (even if it means using their custom board instead of an IO board).


It is my hope also that both project can co-exist on the De10-Nano.


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