TMP100, TMP101

SBOS231I – JANUARY 2002 – REVISED NOVEMBER 2015

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7.3.2.2 Serial Bus Address

To program the TMP100 and TMP101 devices, the master must first address slave devices through a slave

address byte. The slave address byte consists of seven address bits and a direction bit indicating the intent of

executing a read or write operation.

The TMP100 device features two address pins to allow up to eight devices to be addressed on a single I2C

interface. Table 2 describes the pin logic levels used to properly connect up to eight devices. Float indicates the

pin is left unconnected. The state of pins ADD0 and ADD1 is sampled on the first I2C bus communication and

must be set before any activity on the interface.

Table 2. Address Pins and Slave Addresses for the TMP100

ADD1

ADD0

SLAVE ADDRESS

0

0

1001000

0

Float

1001001

0

1

1001010

1

0

1001100

1

Float

1001101

1

1

1001110

Float

0

1001011

Float

1

1001111

The TMP101 device features one address pin and an ALERT pin, allowing up to three devices to be connected

per bus. Pin logic levels are described in Table 3. The address pins of the TMP100 and TMP101 devices are

read after reset or in response to an I2C address acquire request. Following reading, the state of the address

pins is latched to minimize power dissipation associated with detection.

Table 3. Address Pins and Slave Addresses for the TMP101

ADD0

SLAVE ADDRESS

0

1001000

Float

1001001

1

1001010

7.3.2.3 Writing and Reading to the TMP100 and TMP101

Accessing a particular register on the TMP100 and TMP101 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 I2C slave

address byte with the R/W bit LOW. Every write operation to the TMP100 and TMP101 devices requires a value

for the Pointer Register (see Figure 7).

When reading from the TMP100 and TMP101 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 an

I2C 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 I2C slave address byte with the R/W bit

HIGH to initiate the read command; see Figure 8 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 TMP100 and

TMP101 devices remember the Pointer Register value until that value is changed by the next write operation.

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