I'm reading back the following registers:
I used the script posted in the following:
At first, everything is fine and all 3 status registers are set to 1.
When I unplug and replug my cable (without making any configuration changes), often the two PLL-Lock status bits are set to 0 and are stuck like that. TMDS_CLK_A_RAW (the bit that tells you if a clock is detected) is always 1 when the cable is plugged in.
So it appears sometimes the TMDS PLL is not locking. If I reset the ADV7842 and reconfigure it using the script, everything is fine.
I also noticed that if I probe the clock signal on my board with my scope (using an active probe), the PLL locks immediately and the two status bits are now 1. Hopefully that's a clue.
Is there something I'm missing here? Do I need to reset the PLL somehow?
Let me know if you need any more info or measurements.