Last year, Ste from HD Retrovision posted an excellent technical breakdown of how csync is generated and how it applies to retro consoles. It was written for the person who wants to know why these signals work and not just what to do with them; Something I’d sure like to see a lot more of!
Well, Ste’s back with part 2 of his “Engineering csync” series and this time he explains how Hsync and Vsync are typically combined to make csync – And most importantly, why those often fail. This is actually a great explanation as to why some BVM’s (such as the A-Series with the BKM-68x card) don’t process Sega Master System sync properly, as well as why PCE/TG-16 consoles have so much trouble.
I highly recommend it for anyone looking to design analog circuits…or just the curious of you, like me!: https://www.hdretrovision.com/blog/2019/10/10/engineering-csync-part-2-falling-short