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Old 10 July 2015, 00:26   #77
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Join Date: Jul 2015
Location: Lund
Posts: 23
Originally Posted by pandy71 View Post
But this means only one - 1920x1080p50(60) mode must be at the output.
Video can be resized to fill area or not (for pixel acurate just pixel replication/repetition and line replication/repetition mode) - this should create also possible to recreate all 50/60Hz related modes - of course to recreate non TV mode (such as 68, 72 Hz etc modes probably other video modes must be used - list of all HDMI modes is long but not many of them seem to be useful - btw 24Hz modes can be used to emulate A2024 and other non standard video modes - OCS can cheat and ECS/AGA are almost fully reprogrammable - there is only 1 thing constant in Amiga video signal - Pixel clock which in extreme case of S_Hires is equal to 28.xxxx MHz).
Unfortunately, after some testing and tweaking I think 720p is the limit for this hardware. The reason for stretching out the screen is not just to fill up empty space, it is simply because I do not have the time to both read and write from/to 8ns sram at the speed required (74.25Mhz reading and 28Mhz/14Mhz writing). The solution is to read pixels from sram at half rate (e.g. display each pixel twice), then I get a very manageable total maximum speed of 65,125Mhz read/write. Perhaps we will revisit the schematics and come up with something faster, still keeping the price tag down.
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