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TMP102 back to back temperature transmissions

shai kon
Expert 1960 points
Other Parts Discussed in Thread: TMP102

Hello,

Does the TMP102 support back to back temperature transmissions?

These are the steps:

1. I send the I2C address ("10010001") .
2. The device sends an acknowledge for the address.
3. The device sends me the most significant temperature byte.
4. As a master, I acknowledge the first temperature byte.
5. The device sends me the least significant temperature byte. The total 12 bit temperature reading seems to be correct (around 23 degrees C)
6. As a master, I acknowledge the second temperature byte.

Now, here is the problem.

After step 6 (master acknowledges the second temperature byte)  I expect the sensor to send me a new most significant temperature byte reading.}
However, this doesn't happen!
The sensor doesn't send any info. It seems like it expects me to start all over from step 1. 

How can I make it send the readings back to back?  

Any help will be much appreciated.
Regards,
Shai

  • 0
    TI__Expert 3300 points

    Hello Shai,

    Are you at anytime modifying the Configuration Register for this device? Why I ask is because this part has a Shutdown Mode which is enabled by setting the SD bit in the Configuration Register. When the SD bit is set to Logic 1, the part shutdowns after one conversion.

     

    Regards,

    Kartik

  • 0
    TI__Mastermind 27715 points

    Hello Shai,

    The TMP102 will not automatically transmit continuous temperature information on its own. In order to receive continuous measurements, the controller device must be programmed such that it will continuously read from the TMP102 temperature register.

    When programming the loop that will do this, keep in mind that the TMP102 has four user-programmable conversion rates (0.25, 1, 4, and 8 conversion/second) so you may need to program a delay between loop iterations.

    Best regards,

    Ian Williams
    Linear Applications Engineer
    High Performance Linear and Sensing Products

  • 0 in reply to Ian Williams
    Expert 1960 points

    Thanks Ian.


    I use an FPGA to extract the data from the sensor, not an MCU...

    It's not a problem though. I can do it the same loop in hardware.

     

    Regards,

    Shai Kon

  • 0 in reply to Kartik Sinha
    Expert 1960 points

    Hello Kartik,

    I never modify the SD bit.