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Implement 120 Temperature sensors on a single I2C Bus.

Aseem Gupta
Intellectual 305 points
Other Parts Discussed in Thread: MSP430F5438, TMP102, TMP175, PCA9548A

Hi!

 

I need to implement 120 Temperature sensors on a single I2C Bus. Using MSP430F5438 Microcontroler. How would I do the addressing and if TMP102 ok on such an Implementation.

 

Thanks

 

Aseem K Gupta

  • TI__Intellectual 1600 points

    Hi Aseem,

    The TMP102 will only support 4 unique addresses on a single I2C bus.  The MSP430F5438 has 4 USCI's.  So those will cover 16 temperature sensors.  For the remainder, you would have to setup digital pins and write your own I2C protocal to communicate with the TMP102's.

    You might want to consider using the TMP175 if possible.  That device can support 27 unique addresses on a single I2C bus.  So you could communicate with 108 temperature sensors with the 4 USCI's.  You should be able to work with the other 12 from a single pair of digital pins, bit-banged.

     

    Rudye

  • TI__Intellectual 2925 points

    Aseem,

    TI also has a few I2C multiplexers that can be useful for situations like this.  Using a device like the PCA9548A (1 to 8 I2C mux) will allow you to get 8 x the number of devices you would ordinarily get on one I2C bus.  Up to 8 PCA9548A devices can be used on a bus for a total of 64 x the number you would ordinarily get on one I2C bus.

    Regards,

    Dave