AD5245

Rev. B | Page 17 of 20

Table 8

. Write Mode

S 0 1 0 1 1 0 AD0

W

A

X

RS

SD

X

X

X

X

X

A

D7

D6

D5

D4

D3

D2

D1

D0

A

P

Slave Address Byte

Instruction Byte

Data Byte

Table 9. Read Mode

S

0

1

0

1

1

0

AD0

R

A

D7

D6

D5

D4

D3

D2

D1

D0

A

P

Slave Address Byte

Data Byte

S = START condition

P = STOP condition

A = Acknowledge

X = Don’t care

W = Write

R = Read

RS = Reset wiper to midscale 0x80

SD = Shutdown connects wiper to B terminal and open circuits

A terminal, but does not change contents of wiper register

D7, D6, D5, D4, D3, D2, D1, D0 = Data Bits

PS

P

S

SCL

SDA

SCL

FRAME 1

FRAME 2

START BY

MASTER

ACK BY

AD5245

SLAVE ADDRESS BYTE

STOP BY

MASTER

INSTRUCTION BYTE

SDA

0

1

0

1

1

0 AD0 R/W

XRS

X

X

X

X

X

1

9

19

D7

D6

D5

D4

D3

D2

D1

D0

ACK BY

AD5245

FRAME 3

DATA BYTE

1

9

ACK BY

AD5245

SD

Figure 45. Writing to the RDAC Register

NO ACK

BY MASTER

SCL

SDA

01

0

1

1

0

AD0

R/W

D7

D6

D5

D4

D3

D2

D1

D0

1

9

1

9

FRAME 1

FRAME 2

START BY

MASTER

ACK BY

AD5245

SLAVE ADDRESS BYTE

RDAC REGISTER

STOP BY

MASTER

Figure 46. Reading Data from a Previously Selected RDAC Register in Write Mode