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DS90UB960-Q1: Broadcast mode affect on bandwidth and FS

David Shumate
Expert 7985 points
Part Number: DS90UB960-Q1

Hi Team,

Do we have any detailed appnotes/training revolving around using broadcast mode setting?

My customer is trying to optimize camera bring up time and one thought was to use broadcast mode to program all cameras simultaneously but I’m trying to understand the actual implications of this on I2C bandwidth and functional safety. Here are the things I’m trying to understand:

-          What does I2C bandwidth look like for a single imager programmed via broadcast mode vs being programmed independently

  • Ex I would think Ack bits and clock stretching potentially slow down the bandwidth but I’m not sure these are still applicable in broadcast mode

-          How does ACK from imager work?

  • Is everything auto ack’d?
    • If so, how do verify registers were successfully written to? Do we have to go back and read the registers to verify?

 

-          If a 933 is used as the seralizer and we are running in DVP mode instead of using a 953 can we still use broadcast mode from the 960?

-          Will broadcast mode be any different for FPDIV devices?

Thanks for the help!

David

  • 0
    TI__Expert 5480 points

    Hi David, 

    I will look into this and get back to you next week. 

    Thanks 

    SAlly 

  • 0 in reply to Sally Cheung95
    TI__Expert 5480 points

    Hi David, 

    When in broadcast mode, The 960 does not have a way of knowing if one of the remote slaves is busy in broadcast mode. Once it receives an ACK from one of the slaves, it will be ready to broadcast another command. So if you need to verify if all the remote slaves have been written to properly , you will need to go back and check to make sure it's been written to properly. The broad cast mode works the same regardless of FPD3/4/DVP. It works by broadcasting a single command from the host controller to all remote cameras by virtue of using the same Slave Aliases.  The 960 receives the command from the controller, it encodes it and sends copies over all the  FPD-Link III interfaces  to the remote serializers.  The serializers further forward the command to the remote cameras over the separate I2C buses.

    Thanks, 
    SAlly