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DS90UB934-Q1: How to get video resolution information in 934

Betty Guo
Expert 7300 points
Part Number: DS90UB934-Q1

Hi team,

customer use 934 in DVR project, sometimes found black display during normally work. below is abnormal reg value,

we have below questions need your help:

1. does the 934 have reg can to check the received video resolution? for 954, we can check 0x73/74/75/76, how about the 934? we don't find this in d/s

2. comparing the normal reg value, we found their have error in reg 0x4D, what's the meaning of BCC_CRC_ERROR and PARITY_ERROR? are they will cause no image?

3. for CRC error, is it only for back channel not forward channel, right?But, in the datasheet, it show This bit indicates a CRC error has been detected in the forward control channel. we also check the 954 d/s, it also say CRC error in forward channel. 

could you help share comments about above question? thank you.

  • 0
    TI__Mastermind 27990 points

    Hi Betty,

    1) No, the 934 does not have the same Line Counter/Line Length measuring feature as the 954.

    2) CRC Errors and Parity Errors could be caused by a number of reasons (mainly due to packet errors or unexpected changes in the data). But it is normal to get these types of errors when you first power-up. Our recommendation is to first power-up and confirm that you have established a LOCK. Then, clear these error bits by reading the register 0x4D. If these error bits persist after the initial clear, then there may be an issue with how the data is being transferred.

    3) The CRC error bit is being sent over the Forward Channel and Back Channel. This is why it's called Bidirectional Control Channel CRC Error. The FPD3 decoder in the SER or DES checks the CRC/Parity bits in the received frame, to detect errors. Since we are talking about the 934 deserializer, it will receive frames over the Forward Channel (SER -> DES). If you look at a serializer datasheet, then the serializer will be able to check CRC errors in frames being sent over the Back Channel (DES -> SER).

    Best,

    Justin Phan

  • 0 in reply to Justin Phan
    TI__Expert 7300 points

    Hi Justin,

    thanks for your reply. if 934 don't have line counter and line length reg, how to check received video resolution?

    thank you

  • 0 in reply to Betty Guo
    TI__Mastermind 27990 points

    Hi Betty,

    The 934 does not have a way to read line length or line count from the received video. This feature is only available for deserializers compatible with CSI-2 serializers, like the 954. The 934 only works with parallel serializers, like the 913/933.

    Best,

    Justin Phan