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DS92LX1621 / DS92LX1622 I²C Bus

Sebastian Miesner
Prodigy 50 points
Other Parts Discussed in Thread: DS92LX1622, DS92LX1621

Hello I am using the DS92LX1622 /21 in Camera mode. I have an SC18IS600 I²C Master and can communicate with the Deserializer connected direct to the I²C master.

The M/S Pin at the Deserializer is high, so the Deserializer is in slave mode. Now I want to programm the Serializer, connected to drilled two wire kabel. I set the adress of serializer in deserializer (Adr 7). But the Serializer is not responding. In wich mode the serializer has to be? Master / Slave ? I tried both, but nothing happens. 

I can´t find the failure, wich addresses do I have to set? Can anyone help me? Did anyone have a sample code how it works?

Thanks in advance,

Sebastian Miesner 

  • 0
    TI__Expert 3050 points

    Hi Sebastian,

    In a camera mode configuration the Ser (DS92LX1621) is powered down by default. You will need to perform the REMOTE WAKE UP SEQUENCE before you can program the Ser or attempt to receive video data. The REMOTE WAKE UP SEQUENCE can be found in the datasheet.

    The M/S pins of the Des and Ser should always be opposite of one another. So if you set the M/S pin of the Des to HIGH, then the M/S pin of the Ser should be low; or vice versa. Also, I would double check the the PDB pins are set properly.

    If you still have issues after waking up the Ser, you should probe the lock pin of the Des to see if the device is able to lock to the incoming high speed data stream. If you are having trouble obtaining lock let me know so I can provide additional guidance.

    Mike Wolfe

    DPS APPS / SVA

  • 0 in reply to Mike Wolfe
    Prodigy 50 points

    Hello Mike, 

    thanks for your tips. Now I have set the M/S Pin on deserializer high and on Serializer low. I can direct communicate per I²C with the deserializer and want to talk to serializer over 2 wire backwards interface. I did what you wrote to me, first I set register 0h26 to "11000000" and then I set register 0h1 to ""00000100" and afterwards I set Register 0h26 back to "00000000".
    From datasheet I understand that  this carry out an Wakeup sequence to the serializer. But when I try to communicate with the serializer then it dosn´t answer. Only when I set auto acknowledge (des reg 3 bit 1) , then the deserializer acknowledge my request, but the serializer dosn´t get anythink. Is there an spezial order for setting the register, am I doing anythink wrong?

    So don´t misunderstand me, the connection from serializer to deserializer works perfectly, but I have to set the Reg 3 bit 0 to '1' , because my data is valid on falling edge. This I only can change  by programming over I²C and this dosn´t work. 

    best regards,

    Sebastian Miesner

  • 0 in reply to Sebastian Miesner
    TI__Expert 7395 points

    Hi Sebastian, 

    Can you confirm the i2c physical device address set on the Ser by CAD pin? Make sure the address programmed into Des reg 0x07 matches the Ser physical address when communicating with the Ser. 
    As for AUTO-ACK, it should be used very carefully. Under very controlled circumstances, it can be used to access the Serializer remotely. 
    Dac Tran 
    APPS / SVA
  • 0 in reply to Dac Tran
    TI__Expert 3050 points

    Sebastian,

    Did you probe the lock pin like I recommended? Under normal circumstances you should not need to use the AUTO-ACK feature. As Dac mentioned please double check the I2C addresses you have programmed into the devices versus what the ID[x] is set to.

    And if you notice any glitches on the lock pin of the DES, please let me know. This is a typically a sign of excessive jitter coming from the image sensor.

    Mike Wolfe

    DPS APPS / SVA