I've been researching microcontrollers with the goal of outputting NTSC and/or PAL video signals.
And when I look at the microcontroller specifications, it appears to me that the single most important factor in determining if a microcontroller can generate analog video, is whether or not it has a clock/PLL/timer/counter that can be divided/multiplied such that somehow it is able to output a frequency that matches the required NTSC/PAL video frequency.
And more specifically, it needs the PLL to be fractional so that the clock timers can be divided very precisely because video requires very precise timing.
Is this correct? Am I on the right track, that basically, a microcontroller with a fractional PLL is able to generate NTSC/PAL video, whilst a microcontroller without fractional PLL is not able to generate NTSC/PAL video?
Or do I have it wrong, is the fractional PLL not so important, maybe the required frequency can be generated in some other way that would match the analog frequencies?
I am trying to identify, when I look at the specs of a microcontroller, if it is, or is not able to generate an analog video signal. I do understand that many other factors are important in working out if it can do so, but my understanding is, that if you cannot control the output frequency of one of the peripherals to an analog TV output frequency, then nothing else matters - the job cannot be done. I am trying to confirm if my understanding is correct or not.
What I am really trying to understand is whether any given MCU can generate the required frequencies without using external components - such as providing an external clock crystal.
I'm talking abut generating a composite signal.