Command Select Address

Power-On-Default State

Register

Name

Register Function

Read Address

Write Address

decimal

12h

12h

0000 0000

0

RTOLB

Remote Temperature Offset Low

Byte

13h

13h

0000 0000

0

RHSLB

Remote HIGH Setpoint Low Byte

14h

14h

0000 0000

0

RLSLB

Remote LOW Setpoint Low Byte

19h

19h

0110 1110

110

RCS

Remote T_CRIT Setpoint

20h

20h

0101 0101

85

LCS

Local T_CRIT Setpoint

21h

21h

0000 1010

10

TH

T_CRIT Hysteresis

B0h-BEh

B0h-BEh

Manufacturers Test Registers

BFh

BFh

0000 0000

0

RDTF

Remote Diode Temperature Filter

FEh

NA

0000 0001

1

RMID

Read Manufacturer’s ID

FFh

NA

LM89 0011 0001

LM89-1 0011 0100

49

52

RDR

Read Stepping or Die Revision

Code

2.2 LOCAL and REMOTE TEMPERATURE REGISTERS (LT, RTHB, RTLB)

(Read Only Address 00h, 01h):

BIT

D7

D6

D5

D4

D3

D2

D1

D0

Value

SIGN

64

32

16

8

4

2

1

For LT and RTHB D7–D0: Temperature Data. LSB = 1˚C. Two’s complement format.

(Read Only Address 10h):

BIT

D7

D6

D5

D4

D3

D2

D1

D0

Value

0.5

0.25

0.125

0000

0

For RTLB D7–D5: Temperature Data. LSB = 0.125˚C. Two’s complement format.

The maximum value available from the Local Temperature register is 127; the minimum value available from the Local

Temperature register is -128. The maximum value available from the Remote Temperature register is 127.875; the minimum value

available from the Remote Temperature registers is −128.875.

2.3 STATUS REGISTER (SR)

(Read Only Address 02h):

D7

D6

D5

D4

D3

D2

D1

D0

Busy

LHIGH

LLOW

RHIGH

RLOW

OPEN

RCRIT

LCRIT

Power up default is with all bits “0” (zero).

D0: LCRIT: When set to “1” indicates a Local Critical Temperature alarm.

D1: RCRIT: When set to “1” indicates a Remote Diode Critical Temperature alarm.

D2: OPEN: When set to “1” indicates a Remote Diode disconnect.

D3: RLOW: When set to “1” indicates a Remote Diode LOW Temperature alarm

D4: RHIGH: When set to “1” indicates a Remote Diode HIGH Temperature alarm.

D5: LLOW: When set to “1” indicates a Local LOW Temperature alarm.

D6: LHIGH: When set to “1” indicates a Local HIGH Temperature alarm.

D7: Busy: When set to “1” ADC is busy converting.

2.4 CONFIGURATION REGISTER

(Read Address 03h /Write Address 09h):

D7

D6

D5

D4

D3

D2

D1

D0

ALERT mask

RUN/STOP

0

Remote

T_CRIT_A

mask

0

Local

T_CRIT_A

mask

0

Fault Queue

Power up default is with all bits “0” (zero)

D7: ALERT mask: When set to “1” ALERT interrupts are masked.

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