I'm trying to build a simple test pattern generator using a rpi 2040 (aka pico) and using the scanline functions have managed to get seperate HSYNC and VSYNC working at my desired 15.6kHz scan rate... visible area is 256x224
Now I need to move on to making Combined Sync (since this is what one of my monitors supports)...
Looking at several arcade schematics I see nHSYNC AND nVSYNC used for nCMPSYNC
I could do this... but then I saw a video where the HSYNC was present during the VSYNC period but inverted?
Please could you point me at something that defines what composite sync should look like!
Thanks in advance