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TMP103

SBOS545D – FEBRUARY 2011 – REVISED DECEMBER 2018

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7.5.7 Serial Interface

The TMP103 operates as a slave device only on the two-wire bus and SMBus. Connections to the bus are made

through the open-drain I/O lines SDA and SCL. The SDA and SCL pins feature integrated spike suppression

filters and Schmitt triggers to minimize the effects of input spikes and bus noise. The TMP103 supports the

transmission protocol for both fast (1 kHz to 400 kHz) and high-speed (1 kHz to 3.4 MHz) modes. All data bytes

are transmitted MSB first.

7.5.8 Serial Bus Address

To communicate with the TMP103, 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 that indicates the intent of executing a

read or write operation.

The TMP103 is available in eight versions, each with a different slave address, as shown in Table 2. These

addresses can be used as either a location or a temperature zone designator.

Table 2. Device Slave Addresses

PRODUCT

TWO-WIRE ADDRESS

TEMPERATURE ZONE

TMP103A

1110000

Zone1

TMP103B

1110001

Zone2

TMP103C

1110010

Zone3

TMP103D

1110011

Zone4

TMP103E

1110100

Zone5

TMP103F

1110101

Zone6

TMP103G

1110110

Zone7

TMP103H

1110111

Zone8

7.5.9 Writing and Reading Operation

Accessing a particular register on the TMP103 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 TMP103 requires a value for the Pointer Register (see Figure 2).

When reading from the TMP103, 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 3 for details of this sequence. If repeated reads from the same register are desired, it is not

necessary to continually send the Pointer Register bytes; the TMP103 remembers the Pointer Register value

until it is changed by the next write operation, or the TMP103 is reset.

7.5.10 Slave Mode Operations

The TMP103 can operate as a slave receiver or slave transmitter. As a slave device, the TMP103 never drives

the SCL line.

7.5.10.1 Slave Receiver Mode

The first byte transmitted by the master is the slave address, with the R/W bit low. The TMP103 then

acknowledges reception of a valid address. The next byte transmitted by the master is the Pointer Register. The

TMP103 then acknowledges reception of the Pointer Register byte. The next byte is written to the register

addressed by the Pointer Register. The TMP103 acknowledges reception of the data byte. The master can

terminate data transfer by generating a START or STOP condition.