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TMP422: Access to Temperature Registers during the Temperature ADCs are busy, slave address for single-byte read

Part Number: TMP422


I have the following two questions:

  1. could the master device access the Local Temperature Register and the Remote Temperature Registers during the Temperature ADCs are busy?
  2. In Figure 18 of the TMP422 datasheet (SB)S398C-July 2007-Revised May 2012), it shows the Slave address needs to be sent after the Pointer Register Byte.  If there is only one TMP422 in the SMBus, does the slave address needs to be sent twice during the Single-Byte Read, i.e. sent after the Start bit, then sent again after the Pointer Register Byte?


Best regards,


  • Hi Mark,

    See my responses below:

    1. This is ok, you will be reading the last conversion.
    2. The reason for this is because you need to issue a write command, point to the register, and then issue a repeated start with the device address and read command. This is standard I2C communication procedure. The screenshot below shows the communication block. For more info, check out this app report on I2C.

    Best regards,

    Simon Rojas