X9241A

FN8164 Rev 7.00

Page 5 of 17

August 17, 2015

WCR current wiper position to a Data Register is a write to

The transfer can occur between one of the four potentiometers

and one of its associated registers; or it may occur globally,

wherein the transfer occurs between all four of the

potentiometers and one of their associated registers.

Four instructions require a three-byte sequence to complete.

These instructions transfer data between the host and the

X9241A; either between the host and one of the Data

Registers or directly between the host and the WCR. These

instructions are: Read WCR, read the current wiper position of

the selected pot; Write WCR, change current wiper position of

the selected pot; Read Data Register, read the contents of the

selected nonvolatile register; Write Data Register, write a new

value to the selected Data Register. The sequence of

operations is shown in Figure 4.

The Increment/Decrement command is different from the other

commands. Once the command is issued and the X9241A has

responded with an acknowledge, the master can clock the

selected wiper up and/or down in one segment steps; thereby,

providing a fine tuning capability to the host. For each SCL

Similarly, for each SCL clock pulse while SDA is LOW, the

selected wiper will move one resistor segment towards the

timing for this operation is shown in Figures 5 and 6

respectively.

S

T

A

R

T

0101

A3

A2

A1

A0

A

I3

I2

I1

I0

P1

P0

R1

R0

SCL

SDA

S

T

O

P

C

K

A

C

K

FIGURE 3. TWO-BYTE INSTRUCTION SEQUENCE

S

T

A

R

T

0

1

0

1

A3 A2 A1 A0

A

I3

I2

I1

I0

P1 P0 R1 R0

SCL

SDA

S

T

O

P

CM DW D5 D4 D3 D2

D1 D0

C

K

A

C

K

A

C

K

FIGURE 4. THREE-BYTE INSTRUCTION SEQUENCE

S

T

A

R

T

0

1

0

1

A3

A2A1A0

I3

I2

I1

I0

P1 P0

R1 R0

SCL

SDA

S

T

O

P

X

X

I

N

C

1

I

N

C

2

I

N

C

n

D

E

C

1

D

E

C

n

A

C

K

A

C

K

FIGURE 5. INCREMENT/DECREMENT INSTRUCTION SEQUENCE