Sidequest: VGA scan doubler

[Aeberbach]

Interlaced display is alternate display of lines unless I misunderstand. Wouldn’t you have to buffer at least one full even frame then combine it with the coming odd frame to output the combined non-interlaced frame?

[Smonson]

Oh, yeah I guess you're right. Interlaced video is a bit of a problem.

[Aeberbach]

Still looking. Hard to find async, wide, SRAM in a prototypable package.

[Aeberbach]

https://au.mouser.com/datasheet/2/12/Al ... 265408.pdf

Too bad about the BGA and the price but this looks like the fast async SRAM that is wide enough for RGB8:8:8 and big enough for deinterlacing the highest Amiga resolutions. But not a terrible price considering the cost of available scan doublers/deinterlacers.

[Smonson]

How about two of these? https://au.mouser.com/ProductDetail/ISS ... VRZQ%3D%3D

I guess you will need 3x 24-bit buffers in total. Two one line in length for the scandoubler functionality, and one giant one to hold the previous field for the deinterlacer.

[xyzzy76]

I think you're describing a flicker-fixer, not a scan doubler.

[Aeberbach]

I’m interested in both but smonson’s original is a scan doubler.

I did find those ISSI parts but for simplicity will get started with three 512Kx8. Should be able to put them all on the same buses and select R, G, B with /CE. I also have level shifters, video DAC and prototyping breakouts on the way too. Will start by reversing a plcc socket on top of the video DAC in the A1200 and breadboarding it out to my own DAC, then start trying to manipulate bits in the middle.

[Smonson]

My PCBs haven't moved beyond 10% at Seeed Studio since ordering them 3 weeks ago. But I wasn't too worried about it, because their site has had a banner at the top saying something along the lines of "due to a system upgrade the status of some orders is not visible, sorry for the inconvenience". I chose the ultra-slow shipping option to save on cost so I figured they were in-flight somewhere.

But when that banner disappeared I decided to send them an email and they said "oh... shit, your order got missed" - so I'm getting them expedited and then DHL'd to me. They fucked the order up but their customer service is excellent, so I'm still happy. Fingers crossed there'll be some movement on this project soon.

[DoG]

Oh, that kind of thing sucks.

[Icky]

So annoying, especially when you are eagerly awaiting parts for your project to move to the next phase.