disabling the timer is quite important, each scan line in the signal must take 63( +/- 0.5)us, if the interrupt fires during the line generation, it will blow out the timing significantly, I will try to take a picture of what I get when the timer is NOT disabled, then you can compare what you're getting.



I'm not too sure how to disable it on the amtega8, but try using agent_orange's solution of 'cli();' somewhere in the setup() routine.



with regards to the 75ohm resistor, I can't be sure how critical it is, the most important thing is that you can generate 4 distinct voltages wrt the tv signal pin.



the voltages that you are aiming for are close to:

sync = 0.0v

black = 0.33v

gray = 0.66

white 1v



I was able to generate approx:

sync = 0v

black= 0.30

gray = 0.64

white = 0.95



Check your results with a multimeter first, to see what you get.



Good luck!



Oh, on a side note, I can't verify how correct the PAL signal is, (I don't have an oscilloscope) so I only know that this works on the 2 tvs that I have (which are both pal, but quite new).

If anyone has actually got this working, maybe they could post back with their resistor values and geographical location.



Al