I'm kind of following up on my "hacking a TFT" display. With respect to that, I've since noticed that there are some good (albeit soporific) webinars on the Microchip website describing how to interface various LCD displays (including QVGA TFTs) to PIC mcus.
Anyways, I've digressed a bit and I'm interested in the intermediate step of creating an NTSC signal from a PIC to display graphics and text on a CRT TV. I've found this guy on Youtube, who seems to know what he's doing. He seems like a nice guy, as long as you can get past the Natural-Born-Killer vibe:
YouTube - PIC Microcontroller generating PAL TV signal
So what I'm wondering is this: from what I've learned, all the PIC to TV projects are using PAL signals on PAL TVs, which have exactly 64us horizontal scan lines. NTSC doesn't - the horizontal scan is slightly less than that, in order to provide for added coding (for colour, I think) on top of what was the original protocol.
The difference in vert sync frequencies, or the different number of horizontal scan lines, between PAL and NTSC don't seem to me to be as big an issue as the fact that each NTSC horizontal scan line is 63.[something] us long.
How can accommodate the point-something microseconds if I'm using a PIC mcu?. Or do I need to? I'm not sure how big a deal this is. What I've managed to do so far is get a signal into my TV that looks like scrambled video, but all I've had to experiment with is a 16F88 running from its internal oscillator. I think I'll try ordering some 20MHz oscillators, and perhaps some faster ones to push the tolerance of the mcu a bit, and see what I can make happen with some finer time resolutions. I've only managed a time resolution as small as 10us up to now - I know that's not quite good enough to get something happening.
Anyway, any advice on NTSC signal creation would be greatly appreciated!