ADV7180 valid input

I have a simple question, how can I check wheather ADV7180 has a valid input or not? Possible scenarios are:

- No input at all, input is not connected till power-up,

- Valid input at the beginnig then it is remove (So I need to poll somehow?)

Actually, status register seems to be related with this, IN_LOCK and LOST_LOCK should be usefull. However, when I poll IN_LOCK bit which I suppose current simoltaneous "lock" information, I observe that it is not stable. Although I have an valid input, this bits reports the opposite many times, meanwhile I can observe steady output. (I have an FPGA system which is fed a PAL video by ADV7180 and outputs it to a display)

What other methods would you suggest me to use for a reliable check for a valid input.

Thank you in advance

Mehmet U. Buyuksahin

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  • Thank you,

    INST_HLOCK seems to be usefull as well as IN_LOCK. I will try polling both. However, 3 bits AD_RESULT has 8 differrent detected standard result, I coulnt find information about what happens when nothing detected.

    FREE_RUN_ACK could also be used I guess, but I am not sure whether it is set when lock is lost or it just indicates that the blue screen mode is enabled. Anyway, I guess, this would be an indirect approach. I need to observe what triggers blue screen output.

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  • Thank you,

    INST_HLOCK seems to be usefull as well as IN_LOCK. I will try polling both. However, 3 bits AD_RESULT has 8 differrent detected standard result, I coulnt find information about what happens when nothing detected.

    FREE_RUN_ACK could also be used I guess, but I am not sure whether it is set when lock is lost or it just indicates that the blue screen mode is enabled. Anyway, I guess, this would be an indirect approach. I need to observe what triggers blue screen output.

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