LTC4151/LTC4151-1

9

41511fa

SCL

SDA

START

CONDITION

STOP

CONDITION

ADDRESS

R/W

ACK

DATA

ACK

DATA

ACK

1 - 7

8

9

41511 F02

a6 - a0

b7 - b0

b7 - b0

1 - 7

8

9

1 - 7

8

9

P

S

terface to provide access to six ADC data registers and

a control register for monitoring the measured voltages.

Figure 2 shows a general data transfer format using the

devices and support SMBus Read Byte, Write Byte, Read

Word and Write Word commands. The devices also sup-

port Read Page and Write Page commands that allow one

to read or write more than two bytes of data. When using

the Read Page and Write Page commands, the host need

only to issue an initial register address and the internal

register address pointer automatically increments by 1

after each byte of data is read or written. After the register

address reaches 06h, it will be reset to 00h and continue

the increment. Upon a Stop condition, the register address

is reset to 00h. If desired, the Read Page and Write Page

support can be disabled by clearing control register bit

G3. The data formats for the above commands are shown

in Figures 3 to 8.

APPLICATIONS INFORMATION

Figure 3. LTC4151 Serial Bus SDA Write Byte Protocol

Figure 4. LTC4151 Serial Bus SDA Write Word Protocol

Figure 5. LTC4151 Serial Bus SDA Write Page Protocol

S

ADDRESS

1 1 0 a3:a0

FROM MASTER TO SLAVE

FROM SLAVE TO MASTER

A: ACKNOWLEDGE (LOW)

A: NOT ACKNOWLEDGE (HIGH)

R: READ BIT (HIGH)

COMMAND

DATA

X X X X X b2:b0

0

W

00

0

b7:b0

A

A

AP

41511 F03

W: WRITE BIT (LOW)

S: START CONDITION

P: STOP CONDITION

S

ADDRESS

1 1 0 a3:a0

COMMAND

DATA

DATA

X X X X X b2:b0

0

W

00

0

0

41511 F04

b7:b0

b7:b0

A

A

A

AP

S

ADDRESS

1 1 0 a3:a0

COMMAND

0

X X X X X b2:b0

0

W

00

41511 F05

A

A

AP

b7:b0

DATA

0

A

b7:b0

DATA

0

A

...

...

b7:b0

DATA

Figure 6. LTC4151 Serial Bus SDA Read Byte Protocol

S

ADDRESS

1 1 0 a3:a0

1 1 0 a3:a0 1 0

COMMAND

S

ADDRESS

R A

b7:b0 1

DATA

X X X X X b2:b0

0

W

00

41511 F06

A

A

A P

Figure 7. LTC4151 Serial Bus SDA Read Word Protocol

Figure 8. LTC4151 Serial Bus SDA Read Page Protocol

S

ADDRESS

1 1 0 a3:a0

1 1 0 a3:a0 1 0

COMMAND

S

ADDRESS

R A

b7:b0

1

DATA

X X X X X b2:b0

0

W

00

41511 F07

A

0

A

b7:b0

DATA

A

A P

S

ADDRESS

1 1 0 a3:a0

1 1 0 a3:a0 1 0

COMMAND

S

ADDRESS

R A

b7:b0

1

DATA

X X X X X b2:b0

0

W

00

41511 F08

A

0

A

b7:b0

DATA

A

A P

...

...

b7:b0

DATA