X9511 Datasheet, PDF (3/9 Pages) Xicor Inc. – PushPot O Potentiometer (Push Button Controlled)

X9511
PIN DESCRIPTIONS
V_H/R_H and V_L/R_L
The high (VH/RH) and low (VL/RL) terminals of the
X9511 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is -5V
and the maximum is +5V. It should be noted that the
terminology of VL/RL and VH/RH reference the relative
position of the terminal in relation to wiper movement
direction selected by the PU and PD inputs, and not the
voltage potential on the terminal.
PU
The debounced PU input is for incrementing the wiper
position. An on-chip pull-up holds the PU input HIGH.
A switch closure to ground or a LOW logic level will,
after a debounce time, move the wiper to the next
adjacent higher tap position.
PD
The debounced PD input is for decrementing the wiper
position. An on-chip pull-up holds the PD input HIGH.
A switch closure to ground or a LOW logic level will,
after a debounce time, move the wiper to the next
adjacent lower tap position.
ASE
The debounced ASE (AUTOSTORE enable) pin can
be in one of two states:
V_IL - AUTOSTORE is enabled. When V_CC powers
down, an automatic store cycle takes place.
V_IH - AUTOSTORE is disabled. A LOW to HIGH will
initiate a manual store operation. This is for the user
who wishes to connect a push button switch to this pin.
For every valid push, the X9511 will store the current
wiper position to the EEPROM.
PIN CONFIGURATION
DIP/SOIC
PU 1
8
V_CC
PD 2
7 ASE
V_H
X9511
3
6
V_L
V_SS
4
5
V_W
PIN NAMES
Symbol
V_H/R_H
V_W/R_W
V_L/R_L
V_SS
V_CC
PU
PD
ASE
Description
High Terminal
Wiper Terminal
Low Terminal
Ground
Supply Voltage
Push Up Input
Push Down Input
AUTOSTORE Enable Input
DEVICE OPERATION
There are three sections of the X9511: the input control,
counter and decode section; the EEPROM memory;
and the resistor array. The input control section oper-
ates just like an up/down counter. The output of this
counter is decoded to turn on a single electronic switch,
connecting a point on the resistor array to the wiper out-
put. Under the proper conditions the contents of the
counter can be stored in EEPROM memory and
retained for future use. The resistor array is comprised
of 31 individual resistors connected in series. At either
end of the array and between each resistor is an elec-
tronic switch that transfers the potential at that point to
the wiper.
The X9511 is designed to interface directly to two
push button switches for effectively moving the wiper
up or down. The PU and PD inputs increment or dec-
rement a 5-bit counter respectively. The output of this
counter is decoded to select one of the thirty-two wiper
positions along the resistive array. The wiper incre-
ment input, PU and the wiper decrement input, PD are
both connected to an internal pull-up so that they nor-
mally remain HIGH. When pulled LOW by an external
push button switch or a logic LOW level input, the
wiper will be switched to the next adjacent tap posi-
tion.
Internal debounce circuitry prevents inadvertent
switching of the wiper position if PU or PD remain
LOW for less than 40ms, typical. Each of the buttons
can be pushed either once for a single increment/dec-
rement or continuously for a multiple increments/dec-
rements. The number of increments/decrements of the
wiper position depend on how long the button is being
pushed. When making a continuous push, after the
first second, the increment/decrement speed
increases. For the first second the device will be in the
slow scan mode. Then if the button is held for longer
than 1 second the device will go into the fast scan
mode. As soon as the button is released the X9511
will return to a standby condition.
3
FN8205.1
September 6, 2005