3
FN8165.3
August 29, 2006
PIN DESCRIPTIONS
Serial Output (SO)
SO is a 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 is the serial data input pin. All opcodes, byte
addresses and data to be written to the pots and pot
registers 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
X9250.
Chip Select (CS)
When CS is HIGH, the X9250 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 X9250, 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.
Hold (HOLD)
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
communication, 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 X9250. A maximum of 4 devices may occupy the
SPI serial bus.
Potentiometer Pins
VH/RH (VH0/RH0 - VH3/RH3), VL/RL (VL0/RL0 -
VL3/RL3)
The RH and RL pins are equivalent to the terminal
connections on a mechanical potentiometer.
VW/RW (VW0/RW0 - VW3/RW3)
The wiper pins are equivalent to the wiper terminal of a
mechanical potentiometer.
Hardware Write Protect Input (WP)
The WP pin when LOW prevents nonvolatile writes to
the Data Registers.
Analog Supplies (V+, V-)
The analog supplies V+, V- are the supply voltages for
the XDCP analog section.
PIN CONFIGURATION
PIN NAMES
Symbol
Description
SCK
Serial Clock
SI, SO
Serial Data
A0-A1
Device Address
VH0/RH0–VH3/RH3,
VL0/RL0–VL3/RL3
Potentiometer Pins
(terminal equivalent)
VW0/RW0–VW3/RW3
Potentiometer Pins
(wiper equivalent)
WP
Hardware Write Protection
V+,V-
Analog Supplies
VCC
System Supply Voltage
VSS
System Ground
NC
No Connection
S0
A0
VW3/RW3
V+
VCC
VL0/RL0
1
2
3
4
5
6
7
8
9
10
24
23
22
21
20
19
18
17
16
15
HOLD
SCK
VL2/RL2
VH2/RL2
VW2/RW2
V–
VSS
VW1/RW1
VH1/RH1
VL1/RL1
SOIC/TSSOP
X9250
VH3/RH3
14
13
11
12
VL3/RL3
VH0/RH0
VW0/RW0
CS
A1
SI
WP
X9250