X9271_11 Datasheet, PDF (5/22 Pages) Intersil Corporation – Single, Digitally Controlled (XDCP™) Potentiometer

X9271
PIN DESCRIPTIONS
Bus Interface Pins
SERIAL OUTPUT (SO)
The Serial Output (SO) is the 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)
The Serial Input (SI) is the serial data input pin. All
operational codes, byte addresses, and data to be
written to the potentiometers and potentiometer
registers are input on this pin. Data is latched by the
rising edge of the serial clock.
SERIAL CLOCK (SCK)
The Serial Clock (SCK) input is used to clock data into
and out of the X9271.
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 under way, 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. CMOS level input.
DEVICE ADDRESS (A1 - A0)
The Device Address (A1 - A0) inputs are used to set
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
X9271.
CHIP SELECT (CS)
When Chip Select (CS) is HIGH, the X9271 is
deselected, the SO pin is at high impedance, and
(unless an internal write cycle is under way) the device
is in standby state. CS LOW enables the X9271,
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.
Potentiometer Pins
R_H, R_L
The R_H and R_L pins are equivalent to the terminal
connections on a mechanical potentiometer.
R_W
The wiper pin (R_W) is equivalent to the wiper terminal
of a mechanical potentiometer.
Supply Pins
SYSTEM SUPPLY VOLTAGE (V_CC) AND SUPPLY GROUND (V_SS)
The System Supply Voltage (V_CC) pin is the system
supply voltage. The Supply Ground (V_SS) pin is the
system ground.
Other Pins
HARDWARE WRITE PROTECT INPUT (WP)
The Hardware Write Protect Input (WP) pin, when
LOW, prevents nonvolatile writes to the data registers.
NO CONNECT
No Connect pins should be left floating. These pins
are used for Intersil manufacturing and testing
purposes.
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FN8174.3
June 23, 2011