TMP108 datasheet(12/27 Pages) TI2

12 / 27 page

I/O

Control

Interface

SCL

SDA

Temperature

Configuration

LOW

HIGH

Pointer

TMP108

SBOS663A – APRIL 2013 – REVISED SEPTEMBER 2019

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7.5 Programming

7.5.1 Pointer Register

Figure 11 shows the internal register structure of the TMP108. Use the 8-bit pointer register to address a given

data register. The pointer register uses the two LSBs (see Table 12) to identify which of the data registers

respond to a read or write command. Table 3 identifies the bits of the pointer register byte. Table 4 describes the

pointer address of the registers available in the TMP108. The power-up reset value of the P1 and P0 bits is 00.

Figure 11. Internal Register Structure

Table 3. Pointer Register Byte

Table 4. Pointer Addresses

Temperature register (read only, default)

Configuration register (read/write)

TLOW register (read/write)

THIGH register (read/write)

7.5.2 Temperature Register

The temperature register is configured as a 12-bit, read-only register that stores the output of the most recent

conversion. Two bytes must be read to obtain data, as shown in Table 5 and Table 6. Note that byte 1 is the

most significant byte, followed by byte 2, the least significant byte. The first 12 bits are used to indicate

temperature. There is no requirement to read the least significant byte if that information is not needed (for

example, for resolution lower than 1°C). Table 7 summarizes the temperature data format. One LSB equals

0.0625°C. Negative numbers are represented in binary twos complement format. Following power-up or reset,

the temperature register reads 0°C until the first conversion is complete. The unused bits in the temperature

Table 5. Byte 1 of Temperature Register

T11

T10

TMP108 Fiches technique(PDF) 12 Page - Texas Instruments