Detailed Description

The DS4301 is a single nonvolatile digital potentiome-

ter. This 32-position linear potentiometer has an end-to-

end resistance of 200k

Ω, and operates over a wide

2.4V to 5.5V supply voltage range. The wiper position is

controlled by the three interface pins (U/D, CS, and

INC), and the wiper setting can be stored in EEPROM

on command.

Power-Up

has been reached, the stored wiper setting is loaded

DS4301 wiper control pins become active approximate-

been reached.

Wiper Control

Adjusting the wiper of the DS4301 involves using the

Diagram in Figure 2. To enable wiper adjustment, a

high-to-low transition on the CS pin is required. Hold

CS low for the duration of the communication. Doing

this enables the INC pin to change the wiper position.

Set the U/D pin high to increment or low to decrement

the wiper position. The state of the U/D pin should be

from high to low. After the CS pin is active low, a high-

to-low transition on the INC pin moves the wiper in the

direction dictated by the U/D pin. Continue to pulse

INC (high to low) until the desired wiper position is

reached. On the last edge, hold the INC line low. With

the desired wiper position set, there are two ways to

proceed. One method terminates communication with-

out allowing the value of the current wiper position to

be written to the EEPROM. This is done by transitioning

the CS signal to the high state before bringing the INC

signal high. As long as the state of the CS pin is high

before the state of the INC pin goes high, the current

wiper setting is not written to EEPROM. Because the

current wiper setting was not stored to the NV memory,

the previously stored wiper setting, not the current

wiper setting, is loaded from memory if power is cycled

to the device

The other method is used to store a new wiper setting

in the EEPROM. This is done by bringing the state of

state of the CS pin high. Once the states of both CS

and INC pins are high, the current wiper setting is

Nonvolatile, 32-Position Digital Potentiometer

6

_____________________________________________________________________

GND

CS

INC

U/D

CONTROL

LOGIC UNIT

NONVOLATILE

MEMORY

5-BIT

WIPER

SETTING

POS 31

POS 0

H

L

W

Figure 1. Block Diagram

CS

INC

U/D

WIPER STORAGE

CONDITION

WIPER NON-STORAGE

CONDITION

WIPER POSITION

POSITION X

POSITION X + 1

POSITION X

POSITION X - 1

VIL

Figure 2. Timing Diagram