2°C Accurate Remote/Local Temperature

Sensor with SMBus Serial Interface

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13

Status Byte Functions

The status byte register (Table 7) indicates which (if

any) temperature thresholds have been exceeded. This

byte also indicates whether the ADC is converting and

whether there is an open circuit in the remote-diode

DXP–DXN path. After POR, the normal state of all the

flag bits is zero, assuming none of the alarm conditions

are present. The status byte is cleared by any success-

ful read of the status byte, unless the fault persists.

Note that the ALERT interrupt latch is not automatically

cleared when the status flag bit indicating the ALERT is

cleared. The fault condition must be eliminated before

the ALERT can be cleared.

When reading the status byte, check for internal bus

collisions caused by asynchronous ADC timing, or else

disable the ADC prior to reading the status byte

(through the RUN/STOP bit in the configuration byte). In

one-shot mode, read the status byte only after the con-

version is complete, which is 150ms max after the one-

shot conversion is commanded.

BIT

NAME

POR STATE

FUNCTION

7 (MSB)

MASK1

0

Masks ALERT interrupts if high.

6

RUN/STOP

0

Standby mode control bit; if high, standby mode is initiated.

5

ETA

0

If high, lower temperature range is extended from 0

°C to -64°C.

4

PRCM

0

If high, parasitic resistance cancellation mode is enabled.

3

SPNP

0

—

2 to 0

RFU

0

Reserved.

Table 6. Configuration-Byte Bit Assignments

REGISTER

ADDRESS

POR STATE

FUNCTION

RLTS

00h

0000 0000

Read Internal Temperature

RRTE

01h

0000 0000

Read External Temperature

RSL

02h

0000 0000

Read Status Byte

RCL

03h

0000 0000

Read Configuration Byte

RCRA

04h

0000 0010

Read Conversion Rate Byte

RLHN

05h

0111 1111

Read Internal High Limit

RLLI

06h

1100 1001

Read Internal Low Limit

RRHI

07h

0111 1111

Read External High Limit

RRLS

08h

1100 1001

Read External Low Limit

WCA

09h

N/A

Write Configuration Byte

WCRW

0Ah

N/A

Write Conversion Rate Byte

WLHO

0Bh

N/A

Write Internal High Limit

WLLM

0Ch

N/A

Write Internal Low Limit

WRHA

0Dh

N/A

Write External High Limit

WRLN

0Eh

N/A

Write External Low Limit

OSHT

0Fh

N/A

One-Shot

RRET

10h

0000 0000

Read External Extended Temperature

RLET

11h

0000 0000

Read Internal Extended Temperature

N/A

FEh

4D

Read Device ID

N/A

FFh

08

Read Device Revision

Table 5. Command-Byte Bit Assignments