1.8 SERIAL INTERFACE RESET

In the event that the SMBus Master is RESET while the

LM95231 is transmitting on the SMBDAT line, the LM95231

must be returned to a known state in the communication

protocol. This may be done in one of two ways:

1.

When SMBDAT is LOW, the LM95231 SMBus state

machine resets to the SMBus idle state if either SMB-

DAT or SMBCLK are held low for more than 35ms

(t

2.0 all devices are to timeout when either the SMBCLK

or SMBDAT lines are held low for 25-35ms. Therefore, to

insure a timeout of all devices on the bus the SMBCLK

or SMBDAT lines must be held low for at least 35ms.

2.

When SMBDAT is HIGH, have the master initiate an

SMBus start. The LM95231 will respond properly to an

SMBus start condition at any point during the communi-

cation. After the start the LM95231 will expect an SMBus

Address address byte.

1.9 ONE-SHOT CONVERSION

The One-Shot register is used to initiate a single conversion

and comparison cycle when the device is in standby mode,

after which the device returns to standby. This is not a data

register and it is the write operation that causes the one-shot

conversion. The data written to this address is irrelevant and

is not stored. A zero will always be read from this register.

2.0 LM95231 Registers

Command register selects which registers will be read from or written to. Data for this register should be transmitted during the

Command Byte of the SMBus write communication.

P7

P6

P5

P4

P3

P2

P1

P0

Command

P0-P7: Command

Register Summary

Name

Command

(Hex)

Power-On

Default Value

(Hex)

Read/Write

# of used

bits

Comments

Status Register

02h

-

RO

5

4 status bits and 1 busy bit

Configuration Register

03h

00h

R/W

5

Includes conversion rate

control

Remote Diode Filter Control

06h

05h

R/W

2

Controls thermal diode filter

setting

Remote Diode Model Type

Select

30h

01h

R/W

2

Selects the 2N3904 or

Pentium 4 processor on 90nm

process thermal diode model

Remote Diode TruTherm

Mode Control

07h

01h

8

Enables or disables TruTherm

technology for Remote Diode

measurements

1-shot

0Fh

-

WO

-

Activates one conversion for

all 3 channels if the chip is in

standby mode (i.e.

RUN/STOP bit = 1). Data

transmitted by the host is

ignored by the LM95231.

Local Temperature MSB

10h

-

RO

8

Remote Temperature 1 MSB

11h

-

RO

8

Remote Temperature 2 MSB

12h

-

RO

8

Local Temperature LSB

20h

-

RO

2

All unused bits will report zero

Remote Temperature 1 LSB

21h

-

RO

3/5

All unused bits will report zero

Remote Temperature 2 LSB

22h

-

RO

3/5

All unused bits will report zero

Manufacturer ID

FEh

01h

RO

Revision ID

FFh

A1h

RO

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