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Question about LOCK and I2C communication status when startup DS90UB913/914 pair devices

user1118841
Prodigy 30 points

In one of the 913/914 typical application, 913 connect to camera sensor, and 914 connect to AP. So,
1)What's the status of LOCK of 914(in 0x1c of 914 or on LOCK pin) when system startup? At this moment, camera sensor is not initialized. So there is no PCLK, HSYC, DATA. Will the lock status go high?  
2)Should LOCK be high before any I2C communication between 914/913? I mean at which point can I2C communication between 913/914 be established?

Thanks.

  • 0
    Prodigy 30 points
    1) First, I am disappointed with the poor support from this TI site. No one answer the question more than two months
    2)I will reply this for those have the same puzzle
    a)LOCK will be locked whether camera is ready or not. When De/serialize quit reset, the lock will be locked
    b)Before any I2C communication, the LOCK signal must be locked
  • 0 in reply to user1118841
    TI__Intellectual 1820 points
    Hello,

    LOCK is established 22ms max. (tDDLT) after PDB is high. PDB should be high after Power supply voltage has been settled. Please see Figure 12. Deserializer Data Lock Time and "Power-up Requirements and PDB pin" section in the datasheet. So, LOCK is not established and LOCK pin status should be low during system startup.

    Yes, you are right. LOCK should be high before starting I2C communication between 913 and 914. After LOCK is established, it is ready to start I2C communication.

    Best Regards,
    Sugiura
  • 0 in reply to Naomi Sugiura42
    TI__Genius 12705 points
    answered in previous post