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ADV7842 Value of CHx_LCF[10:0] Line Count

Question asked by daisu on Oct 15, 2013
Latest reply on Oct 16, 2013 by daisu

Hello all,


Input video signal to backend is switched to different resolution some time.

Then , the counter CHx_LCF[10:0]  about total number of lines  in component processor is operated incorrectly.

Please let me know your advice below



Video signal (1280*800,  Total line is 831 lines) is processed correctly.
Then we switch from this video signal to another video signal ( 828 total lines. Note 1)  using electrical switcher (SWer. Note2).
But, Value of CHx_LCF is not changed and 831 total lines(Note 3) are read.
And, 828 total lines are read at reverse situation.

Note1: not VESE 1280*800 signal which PC generates when EDID is not received
Note2: Input signal is switched instantaneously so video signal always input to backend.
Note3: Value of CH2_LCF should be 827=0x33b which true value minus 1 but 830=0x33e be always read.


Above issue is critical issue because the system does not recognize resolution correctly.
Please let me know your advice.

1: How can  value of CHx_LCF[10:0] be updated correctly when input signal is switched ?
Please let me know your advice assumed problem in our system.