Functional description

STLM75

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3.1.3

Temperature register

The Temperature register is a two-byte (16-bit) “Read only” register (see Table 7 on

page 18). Digital temperatures from the T-to-D converter are stored in the Temperature

register in two’s complement format, and the contents of this register are updated each time

the T-to-D conversion is finished.

The user can read data from the Temperature register at any time. When a T-to-D

conversion is completed, the new data is loaded into a comparator buffer to evaluate fault

conditions, and will update the Temperature register if a read cycle is not ongoing. The

STLM75 is continuously evaluating fault conditions regardless of READ or WRITE activity

on the bus. If a READ is ongoing, the previous temperature will be read. The readable

temperature will be updated upon the completion of the next T-to-D conversion that is not

masked by a read cycle.

All unused bits following the digital temperature will be zero. The MSB position of the

Temperature register always contains the sign bit for the digital temperature, and Bit14

contains the temperature MSB. All bits in the Temperature register default to zero at power-

up.

Note:

These are comparable formats to the LM75.

3.1.4

programmable upper trip-point temperature for the thermal alarm in two’s complement

format (see Table 8 on page 19). This register defaults to 80°C at power-up (i.e., 0101 0000

0000 0000).

position contains the sign bit for the digital temperature and Bit14 contains the temperature

MSB.

register, and all remaining bits are “Don’t cares”.

Table 7.

Temperature register format

Bytes

HS Byte

LS Byte

Bits

MSB

TMSB

TLSB

LSB

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

STLM75

TD8

(Sign)

TD7

(TMSB)

TD

6

TD

5

TD

4

TD

3

TD

2

TD

1

TD0

(TLSB)

00

00

00

0

Keys: SB = Two’s complement Sign Bit

TMSB = Temperature MSB

TLSB = Temperature LSB

TDx = Temperature Data bits