MAX6642ATT96-T(2003) データシートの表示（PDF） - Maxim Integrated

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MAX6642ATT96-T
(Rev.:2003)

±1°C, SMBus-Compatible Remote/Local Temperature Sensor with Overtemperature Alarm

Maxim Integrated 

±1°C, SMBus-Compatible Remote/Local

Temperature Sensor with Overtemperature Alarm

register was previously selected by a Write Byte

instruction. Use caution when using the shorter proto-

cols in multimaster systems, as a second master could

overwrite the command byte without informing the first

master.

Read temperature data from the read internal tempera-

ture (00h) and read external temperature (01h) regis-

ters. The temperature data format for these registers is

8 bits for each channel, with the LSB representing +1°C

(Table 1).

Read the additional bits from the read extended tem-

perature byte register (10h, 11h), which extends the

data to 10 bits and the resolution to +0.25°C per LSB

(Table 2).

WRITE BYTE FORMAT

S

ADDRESS

WR

ACK

7 BITS

SLAVE ADDRESS: EQUIVA-

LENT TO CHIP-SELECT LINE OF

A 3-WIRE INTERFACE

COMMAND

8 BITS

READ BYTE FORMAT

S ADDRESS WR

ACK

COMMAND

ACK

S

7 BITS

8 BITS

SLAVE ADDRESS: EQUIVA-

LENT TO CHIP SELECT LINE

COMMAND BYTE: SELECTS

WHICH REGISTER YOU ARE

REDING FROM

ACK

DATA

ACK

P

8 BITS

1

DATA BYTE: DATA GOES INTO THE REGISTER

SET BY THE COMMAND BYTE (TO SET

THRESHOLDS, CONFIGURATION MASKS, AND

SAMPLING RATE)

ADDRESS

RD

ACK

DATA

///

P

7 BITS

8 BITS

SLAVE ADDRESS: REPEATED

DUE TO CHANGE IN DATA-

FLOW DIRECTION

DATA BYTE: READS FROM

THE REGISTER SET BY THE

COMMAND BYTE

SEND BYTE FORMAT

S ADDRESS WR

7 BITS

ACK

COMMAND

ACK

P

8 BITS

COMMAND BYTE: SENDS COM-

MAND WITH NO DATA, USUALLY

USED FOR ONE-SHOT COMMAND

S = START CONDITION SHADED = SLAVE TRANSMISSION

P = STOP CONDITION /// = NOT ACKNOWLEDGED

RECEIVE BYTE FORMAT

S ADDRESS RD ACK

DATA

///

P

7 BITS

8 BITS

DATA BYTE: READS DATA FROM

THE REGISTER COMMANDED

BY THE LAST READ BYTE OR

WRITE BYTE TRANSMISSION;

ALSO USED FOR SMBUS ALERT

RESPONSE RETURN ADDRESS

Figure 1. SMBus Protocols

A

B

C

D

EF

G

tLOW tHIGH

SMBCLK

H

IJK

LM

SMBDATA

tSU:STA tHD:STA

tSU:DAT

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

E = SLAVE PULLS SMBDATA LINE LOW

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO SLAVE

H = LSB OF DATA CLOCKED INTO SLAVE

Figure 2. SMBus Write Timing Diagram

tSU:STO tBUF

I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION

M = NEW START CONDITION

6 _______________________________________________________________________________________

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