3
FN8205.3
February 2, 2007
PIN DESCRIPTIONS
V
H
/R
H
and V
L
/R
L
The high (V
H
/R
H
) and low (V
L
/R
L
) 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 V
L
/R
L
and V
H
/R
H
are in reference
to 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
PIN NAMES
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 decrement
a 5-bit counter respectively. The output of this counter
is decoded to select one of the thirty-two wiper posi-
tions along the resistive array. The wiper increment
input, PU
and the wiper decrement input, PD are both
connected to an internal pull-up so that they normally
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 position.
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.
V
H
V
CC
PU
PD
1
2
3
4
8
7
6
5
X9511
DIP/SOIC
V
SS
ASE
V
L
V
W
SYMBOL DESCRIPTION
V
H
/R
H
High Terminal
V
W
/R
W
Wiper Terminal
V
L
/R
L
Low Terminal
V
SS
Ground
V
CC
Supply Voltage
PU Push Up Input
PD
Push Down Input
ASE
AUTOSTORE Enable Input
X9511
