AD5171

Table 9. SDA Bits Definitions and Descriptions

Bit

Description

Bit

Description

S

P

Start Condition.

Stop Condition.

D5, D4, D3,

D2, D1, D0

Data Bits.

A

Acknowledge.

AD0

two AD5171s to be addressed.

X

Don’t Care.

T

OTP Programming Bit. Logic 1 programs wiper

position permanently.

E1, E0

0, 0

0, 1

1, 0

1, 1

OTP Validation Bits.

Ready to Program.

Test Fuse Not Blown Successfully. (For Factory Setup Checking

Purpose Only. Users should not see these combinations).

Fatal Error. Try again.

Programmed Successfully. No further adjustments possible.

Write Bit Pattern Illustrations

SDA

FRAME 1

SLAVE ADDRESS BYTE

FRAME 2

INSTRUCTION BYTE

FRAME 1

DATA BYTE

SCL

ACK. BY

AD5171

ACK. BY

AD5171

ACK. BY

AD5171

STOP BY

MASTER

START BY

MASTER

0

1

1

0

11

0 AD0 R/W

0

X

X

X

X

X

X

X

X

XD5

D4

D3

D2

D1

D0

9

1

9

1

9

Figure 36. Writing to the RDAC Register

SDA

FRAME 1

SLAVE ADDRESS BYTE

FRAME 2

INSTRUCTION BYTE

FRAME 1

DATA BYTE

SCL

ACK. BY

AD5171

ACK. BY

AD5171

ACK. BY

AD5171

STOP BY

MASTER

START BY

MASTER

0

1

1

0

11

0 AD0 R/W

1X

XX

X

X

X

X

X

X

D5

D4D3

D2D1

D0

9

1

9

1

9

Figure 37. Activating One-Time Programming

Read Bit Pattern Illustration

SDA

FRAME 1

SLAVE ADDRESS BYTE

FRAME 2

RDAC REGISTER

SCL

ACK. BY

AD5171

NO ACK. BY

MASTER

STOP BY

MASTER

START BY

MASTER

0

1

1

0

11

0 AD0

E1

E0

D5

D4

D3

D2 D1

D0

91

9

R/W

Figure 38. Reading Data from RDAC Register

For users who prefer to use external controllers, the AD5171

connected to this bus as slave device. Referring to Figure 36,

operates as follows:

1.

The master initiates data transfer by establishing a start

condition, which is when SDA from high-to-low while SCL

is high (Figure 36 and Figure 37). The following byte is the

slave address byte, which consists of the 6 MSBs as a slave

address defined as 010110. The next bit is AD0, which is an

AD0 bits, two AD5171 can be addressed on the same bus

(Figure 39). The last LSB is the R/W bit, which determines

whether data will be read from or written to the slave

device.

The slave whose address corresponds to the transmitted

address responds by pulling the SDA line goes low during

Rev. PrC | Page 15 of 20

Preliminary Technical Data