Dear Dave,
I have following observations regarding NTSC capture:
1. In case Extended output control register (0x04 bit [7]) is set to 1 (ITU-R BT.656-4 compatible) then ADV7180 behaves as follows:
a. When NTSC source is connected - The size of each field is (720 X 243) or (720 X 244).
b. When in free-run mode (previously NTSC source connected) - The size of each field is (720 X 233) or (720 X 234).
2. In case Extended output control register (0x04 bit [7]) is set to 0 (ITU-R BT.656-3 compatible) then ADV7180 behaves as follows:
a. When NTSC source is connected - The size of each field is (720 X 243) or (720 X 244).
b. When in free-run mode (previously NTSC source connected) - The size of each field is (720 X 243) or (720 X 244).
Why ADV7180 is behaving differently when video source is connected and in free-run mode when set in ITU-R BT.656-4 compatible mode?
Thanks and Regards,
Varun