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CCS/TMP112: TMP112 design issue

Part Number: TMP112

Tool/software: Code Composer Studio

Hello guys,

I design the tmp112 circuit like the following:

Is it ok to leave the alert pin open and ground the ADD0 pin through a capacitor?

Thanks,

Jianlin

  • Hi Jianlin,

    It is OK to leave the ALERT open. I'm not sure if C14 will cause you issues. I recommend replacing C14 with 0ohm resistor.

    Ren
  • Hello Ren,

    Thanks for your quick response. Can I just directly ground the ADD0?
    If the MCU's clock changed a little by switching from external crystal to internal one, would it influence the I2C communication a lot?

    Thanks,
    Jianlin
  • Yes, ADD0 should be connected to ground to configure I2C Address 0x48.

    The TMP112 is a slave device which supports a wide range of SCL frequencies. The master controls the SCL and SDA bus lines with regards to its reference clock. By design, the master should maintain relative timing specifications with regards to SCL and SDA. This relative timing is the most critical for communication integrity. Absolute frequency does not matter much in I2C. The master could pause communication while it tends to something else, and the slave would not mind (up to the Timeout limit.) This is because I2C is not based on time based frames like UART.

    You might be interested in the following documents if you're new to I2C.
    www.ti.com/.../slva704.pdf
    www.nxp.com/.../UM10204.pdf

    Ren