TMP451

www.ti.com

SBOS686 – JUNE 2013

Table 3. Register Map

POINTER

POINTER

BIT DESCRIPTION

READ

WRITE

(HEX)

(HEX)

POR (HEX)

7

6

5

4

3

2

1

0

REGISTER DESCRIPTION

00

N/A

00

LT11

LT10

LT9

LT8

LT7

LT6

LT5

LT4

Local temperature (high byte)

01

N/A

00

RT11

RT10

RT9

RT8

RT7

RT6

RT5

RT4

Remote temperature (high byte)

02

N/A

N/A

BUSY

LHIGH

LLOW

RHIGH

RLOW

OPEN

RTHRM

LTHRM

status register

ALERT/

03

09

00

MASK1

SD

0

0

RANGE

0

0

configuration register

THERM2

04

0A

08

0

0

0

0

CR3

CR2

CR1

CR0

Conversion rate register

05

0B

55

LTHL11

LTHL10

LTHL9

LTHL8

LTHL7

LTHL6

LTHL5

LTHL4

Local temperature high limit

06

0C

00

LTLL11

LTLL10

LTLL9

LTLL8

LTLL7

LTLL6

LTLL5

LTLL4

Local temperature low limit

Remote temperature high limit (high

07

0D

55

RTHL11

RTHL10

RTHL9

RTHL8

RTHL7

RTHL6

RTHL5

RTHL4

byte)

Remote temperature low limit (high

08

0E

00

RTLL11

RTLL10

RTLL9

RTLL8

RTLL7

RTLL6

RTLL5

RTLL4

byte)

N/A

0F

N/A

X

X

X

X

X

X

X

X

One-shot start

(1)

10

N/A

00

RT3

RT2

RT1

RT0

0

0

0

0

Remote temperature (low byte)

Remote temperature offset (high

11

11

00

RTOS11

RTOS10

RTOS9

RTOS8

RTOS7

RTOS6

RTOS5

RTOS4

byte)

Remote temperature offset (low

12

12

00

RTOS3

RTOS2

RTOS1

RTOS0

0

0

0

0

byte)

Remote temperature high limit (low

13

13

00

RTHL3

RTHL2

RTHL1

RTHL0

0

0

0

0

byte)

Remote temperature low limit (low

14

14

00

RTLL3

RTLL2

RTLL1

RTLL0

0

0

0

0

byte)

15

N/A

00

LT3

LT2

LT1

LT0

0

0

0

0

Local temperature (low byte)

19

19

6C

RTH11

RTH10

RTH9

RTH8

RTH7

RTH6

RTH5

RTH4

Remote temperature THERM limit

20

20

55

LTH11

LTH10

LTH9

LTH8

LTH7

LTH6

LTH5

LTH4

Local temperature THERM limit

21

21

0A

HYS11

HYS10

HYS9

HYS8

HYS7

HYS6

HYS5

HYS4

THERM hysteresis

22

22

01

SMBTO

0

0

0

CONAL2

CONAL1

CONAL0

0

Consecutive ALERT

23

23

00

NC7

NC6

NC5

NC4

NC3

NC2

NC1

NC0

η-factor correction

24

24

00

0

0

0

0

0

0

DF1

DF0

Digital filter control

FE

N/A

55

0

1

0

1

0

1

0

1

Manufacturer ID

(1)

X = undefined. Writing any value to this register initiates a one-shot start; see the One-Shot Conversion section.

Temperature Registers

The TMP451 has multiple 8-bit registers that hold temperature measurement results. The eight most significant

bits (MSBs) of the local temperature sensor result are stored in register 00h, while the four least significant bits

(LSBs) are stored in register 15h (the four MSBs of register 15h). The eight MSBs of the remote temperature

sensor result are stored in register 01h, and the four LSBs are stored in register 10h (the four MSBs of register

10h). The four LSBs of both the local sensor and the remote sensor indicate the temperature value after the

decimal point (for example, if the temperature result is 10.0625

˚C, the high byte is 0000 1010 and the low byte is

0001 0000). These registers are read-only and are updated by the ADC each time a temperature measurement

is completed.

When the full temperature value is needed, reading the MSB value first causes the LSB value to be locked (the

ADC does not write to it) until it is read. The same thing happens upon reading the LSB value first (the MSB

value is locked until it is read). This mechanism assures that both bytes of the read operation are from the same

ADC conversion. This assurance remains valid only until another register is read. For proper operation, read the

high byte of the temperature result first. Read the low byte register in the next read command; if the LSBs are not

needed, the register may be left unread. The power-on reset value of all temperature registers is 00h.

Copyright © 2013, Texas Instruments Incorporated

Submit Documentation Feedback

11

Product Folder Links: TMP451