the_crayon_king Posted January 9, 2021 Author Share Posted January 9, 2021 16 hours ago, YannAros said: Hi, I've studied a bit the CSYNC stuff, and ended doing 1XXX1 (V5 to V1) that seemed to work with my LCD TVs, then I've found another TV that wasn't syncing good horizontaly. Feedling around I could obtain a stable image by "delaying" the sync signal adding a 47nF cap between sync and GND, however as you delay the sync signal the image gets shifted towards the left. Playing further I've found that using 1XXXX is working on this LCD TV, but not on my other ones working with 1XXX1. Later on I've found another LCD TV that had the same behaviour requiring 1XXXX and some other users of the kit had to do the same. So my PCB comes with a jumper allowing to select either one of these methods. I'm also using V5 as OE input for blanking as you suggest. I took a look at your schematic, that from a high level should work, I didn't look into the details. Mine is using separate resistors for each RGB of each colour, allowing more control over the end result. One thing also regarding component selection, I've done it so that I can get the full PCB assembled and SMD component mounted by JLCPCB, this way, even if the component is a bit more expensive, I have no complex soldering to do. At the end we are not talking about huge costs (assembled PCB for a batch of 30 should be around 4$ without shipment cost and custom fees), I'm adding connectors for convenience but you can solder wires directly on PCB to. This is what it is ooking like in the French Intellivision model that has embedded power supply, I designed it so that it can be mounted where the power supply PCB usually sits: Ok so I looked into the whole 1XXXX thing: 1XXXX is basically sync, blanking and burst all in one. Image rolled on my CRT 1XX10 (burst) happens after hsync (1XXX1) and appears to have blank 1XX00 between it and hsync. This worked on my CRT to get video. There might be other instances of burst that happen too quickly for my CPLD to process. 1XXX1 is more or less what I have been using for sync. 1XXX1 + 1XX10 is combining HSYNC and Burst into one long pulse with blank in-between it. I could with some effort make this one long pulse. This worked on my TV as far as I could tell since I had to cut out alot of colors to make it fit. So the question becomes really what length should hsync be? When you are using 1XXXX you are basically using the blanking period for sync. Why the heck would any TV prefer that is another question. I will have to do some more experiments at some point in the near future. JLPCB is finally offering assembly? I might be able to do some more interesting things in the near future given that information. My poor eyeballs can't take much more hand soldering. At any rate I like what you have done. Something that is mountable is far preferable to drilling into shells. I will eventually make something that replaces the RF modules. Quote Link to comment Share on other sites More sharing options...
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