(24 LD SOIC, TSSOP)
Host Interface Pins
SERIAL CLOCK (SCL)
The SCL input is used to clock data into and out of the X9258.
SERIAL DATA (SDA)
SDA is a bidirectional pin used to transfer data into and out of
the device. 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 “Guidelines for Calculating
Typical Values of Bus Pull-Up Resistors” on page 10.
DEVICE ADDRESS (A0 - A3)
The Address inputs are used to set the least significant 4 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 X9258. A maximum of 16
devices may occupy the 2-wire serial bus.
VH/RH (VH0/RH0 - VH3/RH3), VL/RL (VL0/RL0 - VL3/RL3)
The VH/RH and VL/RL inputs are equivalent to the terminal
connections on either end of a mechanical potentiometer.
VW/RW (VW0/RW0 - VW3/RW3)
The wiper outputs are equivalent to the wiper output of a
Hardware Write Protect Input (WP)
The WP pin when low prevents nonvolatile writes to the Data
Analog Supplies V+, V-
The Analog Supplies V+, V- are the supply voltages for the
DCP analog section.
A0 thru A3
VH0/RH0 thru VH3/RH3,
VL0/RL0 thru VL3/RL3
VW0/RW0 thru VW3/RW3
Hardware Write Protection
System Supply Voltage
No Connection (Allowed)
Principles Of Operation
The X9258 is a highly integrated microcircuit incorporating four
resistor arrays and their associated registers and counters and
the serial interface logic providing direct communication
between the host and the DCP potentiometers.
Serial Interface (2-Wire)
The X9258 supports a bidirectional bus oriented protocol. The
protocol defines any device that sends data onto the bus as a
transmitter and the receiving device as the receiver. The
device controlling the transfer is a master and the device being
controlled is the slave. The master will always initiate data
transfers and provide the clock for both transmit and receive
operations. Therefore, the X9258 will be considered a slave
device in all applications.
FN8168 Rev 6.00
December 15, 2011
Page 3 of 19