|TMP175D||Temperature Sensor With I2C and SMBus Interface in Industry Standard LM75 Form Factor and Pinout|
|TMP175D Datasheet PDF : 33 Pages |
SBOS288L – JANUARY 2004 – REVISED DECEMBER 2015
Table 3. Address Pins and Slave Addresses for the TMP75
126.96.36.199 Writing and Reading to the TMP175 and TMP75
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).
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 9 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.
188.8.131.52 Slave Mode Operations
The TMP175 and TMP75 can operate as a slave receiver or slave transmitter.
184.108.40.206.1 Slave Receiver Mode
The first byte transmitted by the master is the slave address, with the R/W bit low. The TMP175 or TMP75 then
acknowledges reception of a valid address. The next byte transmitted by the master is the Pointer register. The
TMP175 or TMP75 then acknowledges reception of the Pointer register byte. The next byte or bytes are written
to the register addressed by the Pointer register. The TMP175 and TMP75 acknowledge reception of each data
byte. The master can terminate data transfer by generating a START or STOP condition.
220.127.116.11.2 Slave Transmitter Mode
The first byte is transmitted by the master and is the slave address, with the R/W bit high. The slave
acknowledges reception of a valid slave address. The next byte is transmitted by the slave and is the most
significant byte of the register indicated by the Pointer register. The master acknowledges reception of the data
byte. The next byte transmitted by the slave is the least significant byte. The master acknowledges reception of
the data byte. The master can terminate data transfer by generating a Not-Acknowledge on reception of any data
byte, or generating a START or STOP condition.
18.104.22.168 SMBus Alert Function
The TMP175 and TMP75 support the SMBus Alert function. When the TMP75 and TMP175 are operating in
interrupt mode (TM = 1), the ALERT pin of the TMP75 or TMP175 can be connected as an SMBus Alert signal.
When a master senses that an ALERT condition is present on the ALERT line, the master sends an SMBus Alert
command (00011001) on the bus. If the ALERT pin of the TMP75 or TMP175 is active, the devices acknowledge
the SMBus Alert command and respond by returning its slave address on the SDA line. The eighth bit (LSB) of
the slave address byte indicates if the temperature exceeding THIGH or falling below TLOW caused the ALERT
condition. This bit is high if the temperature is greater than or equal to THIGH. This bit is low if the temperature is
less than TLOW. See Figure 10 for details of this sequence.
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