Rainbow-electronics MAX6690 Manual de usuario descargar pdf (Pagina 10)

MAX6690

2°C Accurate Remote/Local Temperature

Sensor with SMBus Serial Interface

10 ______________________________________________________________________________________

Figure 4. SMBus Write Timing Diagram

Figure 5. SMBus Read Timing Diagram

ACK

7 bits

ADDRESS ACKWR

8 bits

DATA ACK

1

P

8 bits

S COMMAND

Write Byte Format

Read Byte Format

Send Byte Format Receive Byte Format

Slave Address: equiva-

lent to chip-select line of

a 3-wire interface

Command Byte: selects which

register you are writing to

Data Byte: data goes into the register

set by the command byte (to set

thresholds, configuration masks, and

sampling rate)

ACK

7 bits

ADDRESS ACKWR S ACK

8 bits

DATA

7 bits

ADDRESS RD

8 bits

/// PS COMMAND

Slave Address: equiva-

lent to chip-select line

Command Byte: selects

which register you are

reading from

Slave Address: repeated

due to change in data-

flow direction

Data Byte: reads from

the register set by the

command byte

ACK

7 bits

ADDRESS WR

8 bits

COMMAND ACK PS ACK

7 bits

ADDRESS RD

8 bits

DATA /// PS

Command Byte: sends com-

mand with no data, usually

used for one-shot command

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

S = Start condition Shaded = Slave transmission

P = Stop condition /// = Not acknowledged

SMBCLK

A = START CONDITION

B = MSB OF ADDRESS CLOCKED INTO SLAVE

C = LSB OF ADDRESS CLOCKED INTO SLAVE

D = R/W BIT CLOCKED INTO SLAVE

AB CD

E

FG H

I

J

SMBDATA

t

SU:STA

t

HD:STA

t

LOW

t

HIGH

t

SU:DAT

KLM

t

SU:STO

t

BUF

E = SLAVE PULLS SMBDATA LINE LOW

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO MASTER

H = LSB OF DATA CLOCKED INTO MASTER

I = MASTER PULLS DATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO SLAVE

K = ACKNOWLEDGE CLEAR PULSE

J = STOP CONDITION, DATA

EXECUTED BY SLAVE

K = NEW START CONDITION

SMBCLK

AB CD

E

FG H

I

J

K

SMBDATA

t

SU:STA

t

HD:STA

t

LOW

t

HIGH

t

SU:DAT

t

HD:DAT

t

SU:STO

t

BUF

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

L

M

F = ACKNOWLEDGE BIT CLOCKED INTO MASTER

G = MSB OF DATA CLOCKED INTO SLAVE

H = LSB OF DATA CLOCKED INTO SLAVE

I = SLAVE PULLS SMBDATA LINE LOW

J = ACKNOWLEDGE CLOCKED INTO MASTER

K = ACKNOWLEDGE CLOCK PULSE

L = STOP CONDITION, DATA EXECUTED BY SLAVE

M = NEW START CONDITION

Figure 3. SMBus Protocols

1 2 ... 5 6 7 8 9 10 11 12 13 14 15 16

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