5
FN8172.4
August 29, 2006
PIN DESCRIPTIONS
Bus Interface Pins
S
ERIAL DATA INPUT/OUTPUT (SDA)
The SDA is a bidirectional serial data input/output pin
for a 2-Wire slave device and is used to transfer data
into and out of the device. It receives device address,
opcode, wiper register address and data sent from an
2-Wire master at the rising edge of the serial clock
SCL, and it shifts out data after each falling edge of
the serial clock SCL.
It is an open drain output and may be wire-ORed with
any number of open drain or open collector outputs.
An open drain output requires the use of a pull-up
resistor. For selecting typical values, refer to the
guidelines for calculating typical values on the bus
pull-up resistors graph.
S
ERIAL CLOCK (SCL)
This input is used by 2-Wire master to supply 2-Wire
serial clock to the X9268.
D
EVICE ADDRESS (A3 - A0)
The address inputs are used to set the least significant
3 bits of the 8-bit slave address. A match in the slave
address serial data stream must be made with the
Address input in order to initiate communication with
the X9268. A maximum of 8 devices may occupy the
2-Wire serial bus.
Potentiometer Pins
R
H
, R
L
The R
H
and R
L
pins are equivalent to the terminal
connections on a mechanical potentiometer. Since
there are 2 potentiometers, there are 2 sets of R
H
and
R
L
such that R
H0
and R
L0
are the terminals of POT 0
and so on.
R
W
The wiper pin are equivalent to the wiper terminal of a
mechanical potentiometer. Since there are 4
potentiometers, there are 2 sets of R
W
such that R
W0
is the terminal of POT 0 and so on.
Bias Supply Pins
S
YSTEM SUPPLY VOLTAGE (V
CC
) AND SUPPLY
G
ROUND (V
SS
)
The V
CC
pin is the system supply voltage. The V
SS
pin is the system ground.
Analog Supply Voltages (V+ and V
-)
These supplies are the analog voltage supplies for the
potentiometer. The V+ supply is tied to the wiper
switches while the V- supply is used to bias the
switches and the internal P+ substrate of the
integrated circuit. Both of these supplies set the
voltage limits of the potentiometer.
Other Pins
N
O CONNECT
No connect pins should be left open. This pins are
used for Intersil manufacturing and testing purposes.
H
ARDWARE WRITE PROTECT INPUT (WP)
The WP
pin when LOW prevents nonvolatile writes to
the Data Registers.
X9268
