Then there's something about PWM that I didn't understand. HIGH/LOW using PAUSE for 500uS is not the same as a 1000uS period with 50% duty cycle?
Yes of course, 500us ON and 500us OFF is 50% dutycyle. But the period is 500us+500us = 1000us = 1ms = 0.001s - NOT 1s which you later wrote.

In your first post you indicated you wanted a PWM period of 1000us (a frequency of 1000Hz). In your second post you said you wanted a period of 1s (a frequency of 1Hz). It doesn't add up - that's all I was trying to say.

/Henrik.