Hi,
I'm trying to generate BW video signals with an at89c52 at 24 MHz. This is based on this page with an PIC uC: rtvideo5.
I'm using two resistor on P1 to make an basic D/A converter like this:

..............900R
P1.0 ---[===]----
..............450R......|--- TV out
P1.1 ---[===]----/

so writing 0 will give me 0V(SYNC), 1 will give aprox .33V(BLACK), 2 = .66V(GREY) and 3 = 1V(WHITE).
There are some random points that apear on the TV, but no matter what delay I put betwen shades it only apears dots... what makes me think that P1 is no latching the values.(Back to 0 always after mov???)
Should I use pullups on P1 for this? Any sugestions?

Gabriel.

PS. I know this works cus I did it before with an Z80.