X9418 Datasheet, PDF(5/21 Page) Xicor Inc. – Dual Digitally Controlled Potentiometers

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X9418 Datasheet, PDF (5/21 Pages) Xicor Inc. – Dual Digitally Controlled Potentiometers

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Figure 3. Two-Byte Instruction Sequence

X9418

SCL

SDA

S 0 1 0 1 A3 A2 A1 A0 A I3 I2 I1 I0 R1 R0 0 P0 A S

The Increment/Decrement command is different from

the other commands. Once the command is issued

and the X9418 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 clock pulse

(tHIGH) while SDA is HIGH, the selected wiper will

move one resistor segment towards the VH/RH

terminal. Similarly, for each SCL clock pulse while

SDA is LOW, the selected wiper will move one resistor

segment towards the VL/RL terminal. A detailed

illustration of the sequence and timing for this

operation are shown in Figures 5 and 6 respectively.

Table 1. Instruction Set

Instruction Set

Instruction

Read Wiper Counter

Write Wiper Counter

Read Data Register

Write Data Register

XFR Data Register to

Wiper Counter Register

I3 I2 I1 I0 R1 R0 P1 P0

Operation

1 0 0 1 0 0 0 1/0 Read the contents of the Wiper Counter Register

pointed to by P0

1 0 1 0 0 0 0 1/0 Write new value to the Wiper Counter Register

pointed to by P0

1 0 1 1 1/0 1/0 0 1/0 Read the contents of the Data Register pointed to by

P0 and R1 - R0

1 1 0 0 1/0 1/0 0 1/0 Write new value to the Data Register pointed to by

P0 and R1 - R0

1 1 0 1 1/0 1/0 0 1/0 Transfer the contents of the Data Register pointed to

by P0 and R1 - R0 to its associated Wiper Counter

XFR Wiper Counter

1 1 1 0 1/0 1/0 0 1/0 Transfer the contents of the Wiper Counter Register

pointed to by P0 to the Data Register pointed to by

R1 - R0

Global XFR Data

0 0 0 1 1/0 1/0 0 0 Transfer the contents of the Data Registers pointed

Registers to Wiper

Counter Registers

to by R1 - R0 of both pots to their respective Wiper

Counter Registers

Global XFR Wiper

Counter Registers to

Data Register

Increment/Decrement

Wiper Counter Register

1 0 0 0 1/0 1/0 0 0 Transfer the contents of both Wiper Counter

Registers to their respective data Registers pointed

to by R1 - R0 of both pots

0 0 1 0 0 0 0 1/0 Enable Increment/decrement of the Wiper Counter

Note: (7) 1/0 = data is one or zero

FN8194.0

March 7, 2005

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