I was wondering if anyone might know some specific details about the PAL GTIA. The data sheets that are out in the wild seem only to cover NTSC. Here are my questions:
- From the schematics of various Ataris, it appears that the PAL pin acts as an input (?) for the PAL color carrier frequency line. Is this right?
- From my understanding, PAL switches color polarity every line and indicates this via changing the polarity of the color burst. Does the PAL GTIA do this? Does this manifest as every other line having inverted hue (i.e. 15-hue), or shifted hue (i.e. 7+hue%15), or what?
- Is the PAL color palette really substantially different from NTSC?
- On NTSC systems, the color clock (one gr.7 or 15 pixel) is 279.4 nS long. For color pixels (hue != 0), the COLOR line goes low at one of fifteen possible times, and the delta between each possible color can be (depending on the CADJ voltage level) anywhere between 16 to 35 nS (that's according to the various data sheets; though only values on or slightly below 18.6 nS would make for "correct" color output, as anything beyond that would result in higher color values bumping into the next pixel). On PAL systems, how does this timing work? Is it relative to the color carrier (PAL line?), or OSC like NTSC? If it's relative to the color carrier, does that mean the possible delay values are much shorter than 16-35 nS?
- Does anyone have any real-world timing measurements for PAL GTIA, or know of a PAL GTIA data sheet?