I tried to search on Google and many result indicated that Arduino don't have the power to generate a full color video via composite because of changing phase shift and frequency but what if Arduino made output in just red, green, blue, and sync? If the timing is right, and the ouytput is connected to a video chip like CX1145 I took out of a Sega Genesis, can it be done?
I'm not looking for fancy graphics, I wanted to build an old school color bar generator so I can properly test older TVs. (all color present? Stead image? sharp edge between bars? etc) New pattern generator starts at over $150 a pop (YIKES) so if I can make one with a $5 chip, an oscillator of optimal frequency, and a dead sega Genesis I got for $5 it would go a long way toward saving costs.
If my memory serves, standard NTSC TV's (both 240i and 480p) horizontal operates at 15,750Hz frequency and each line would change only 8 times in this order: White, Yellow, Cyan, Green, Magenta, Red, then blue before it goes all black for the sync. Some of you are probably aware that color order are actually green the first half, red first and third 1/4, and blue alternating 1/8th (the final 1/8th is not visible on screen as it'd be all black for the sync) I remember reading that the actual signal can be 1Mhz
Can it be done or is that still too fast for arduino to time? ATMega328 can do 20MHz easy, or I could pick up a Due with 84MHz cpu but it seems like a huge board just for a few I/O pins