JAJS009M January 2004 – December 2020 TMP175 , TMP75
PRODUCTION DATA
Accessing a particular register on the TMP175 and TMP75 devices is accomplished by writing the appropriate value to the Pointer register. The value for the Pointer register is the first byte transferred after the slave address byte with the R/W bit low. Every write operation to the TMP175 and TMP75 requires a value for the Pointer register (see Figure 7-2).
When reading from the TMP175 and TMP75 devices, the last value stored in the Pointer register by a write operation is used to determine which register is read by a read operation. To change the register pointer for a read operation, a new value must be written to the Pointer register. This action is accomplished by issuing a slave address byte with the R/ W bit low, followed by the Pointer register byte. No additional data are required. The master can then generate a START condition and send the slave address byte with the R/ W bit high to initiate the read command. See Figure 7-4 for details of this sequence. If repeated reads from the same register are desired, the Pointer register bytes do not have to be continually sent because the TMP175 and TMP75 remember the Pointer register value until the value is changed by the next write operation.
Register bytes are sent MSB first, followed by the LSB.