Datasheet

STTS751 register summary STTS751

14/36 Doc ID 16483 Rev 5

4.1 STTS751 register formats and details

The STTS751 register set is comprised of the 16 addresses shown in Ta bl e 9. The

individual registers are accessed by transferring their addresses via the SMBus interface as

shown in Section 3.2, 3.3, and 3.4. In the case of the RECEIVE byte sequence

(Section 3.5) the address used is the address sent in the previous WRITE, READ or SEND

byte sequence.

An example read sequence of the Therm hysteresis register, address 21h, with its default

value, 0Ah, is shown below. The slave address used is 90h. The gray data is sent by the

STTS751 while the white data is sent by the host.

Note: All eight bits are used to select the register.

4.2 Temperature register format

The temperature data is a 12-bit number and is stored in two's complement format spanning

the high byte and low byte registers as shown in Ta bl e 1 1.

The integer portion of the temperature is stored in the high byte, and the fractional portion in

the low byte. The lower four bits of the low byte will always read 0. At power-up, the

STTS751 defaults to 10-bit resolution. Thus, bits b5 and b4 of the lower byte will also read 0

until the device is configured to a higher resolution (via the Tres bits in the configuration

Table 10. Pointer register format

START

SLAVE

ADDRESS

WR ACK

ADDRESS

ACK START

SLAVE

ADDRESS

RD ACK DATA NACK STOP

1001_000 0 0010_0001 1001_000 1 0000_1010

Table 11. Temperature register (two’s complement)

ADDR

(hex)

R/W Register b7 b6 b5 b4 b3 b2 b1 b0

Power-up

default

(hex)

00 R Temperature - high byte sign 64 °C 32 °C 16 °C 8 °C 4°C 2 °C 1 °C 00

02 R Temperature - low byte

½ °C ¼ °C

°C

°C 0 0 0 0 00