X9430 – Preliminary Information
Host Interface Pins
Serial Output (SO)
SO is a push/pull serial data output pin. During a read
cycle, data is shifted out on this pin. Data is clocked
out by the falling edge of the serial clock.
Serial Input (SI)
SI is the serial data input pin. All opcodes, byte
addresses and data to be written to the device are
input on this pin. Data is latched by the rising edge of
the serial clock.
Serial Clock (SCK)
The SCK input is used to clock data into and out of the
Chip Select (CS)
When CS is HIGH, the X9430 is deselected and the
SO pin is at high impedance, and (unless an internal
write cycle is underway) the device will be in the
standby state. CS LOW enables the X9430, placing it
in the active power mode. It should be noted that after
a power-up, a HIGH to LOW transition on CS is
required prior to the start of any operation.
Hardware Write Protect Input WP
The WP pin when low prevents nonvolatile writes to
the wiper counter register.
HOLD is used in conjunction with the CS pin to select
the device. Once the part is selected and a serial
sequence is underway, HOLD may be used to pause
the serial communication with the controller without
resetting the serial sequence. To pause, HOLD must
be brought LOW while SCK is LOW. To resume com-
munication, HOLD is brought HIGH, again while SCK
is LOW. If the pause feature is not used, HOLD should
be held HIGH at all times.
Device Address (A0–A1)
The address inputs are used to set the least significant
2 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 X9430. A maximum of 4 devices may occupy the
SPI serial bus.
RH (RH0–RH1), RL (RL0–RL1)
The RH and RL inputs are equivalent to the terminal
connections on either end of a mechanical potentiom-
The wiper output is equivalent to the wiper output of a
Amplifier and Device Pins
Amplifier Input Voltage VNI(0,1) and VINV(0,1)
VNI and VINV are inputs to the noninverting (+) and
inverting (-) inputs of the operational amplifiers.
Amplifier Output Voltage VOUT(0,1)
VOUT is the voltage output pin of the operational ampli-
Analog Supplies V+, V-
The Analog Supplies V+, V- are the supply voltages for
the XDCP analog section and the operational amplifi-
System Supply VCC and Ground VSS
The system supply VCC and its reference VSS is used
to bias the interface and control circuits.
1. Alternate designations for RH, RL, RW are VH, VL, VW
REV 1.0 6/20/00
Characteristics subject to change without notice. 2 of 21