X9252
Pin Descriptions (Continued)
PIN #
19
20
21
22
23
SYMBOL
CS
RW2
RH2
RL2
SCL
Chip select for Up/Down interface.
Wiper terminal of DCP2.
High terminal of DCP2.
Low terminal of DCP2.
Serial clock for 2-wire bus.
DESCRIPTION
Pin Descriptions
Bus Interface Pins
Serial Data Input/Output (SDA)
The SDA is a bidirectional serial data input/output pin for the 2-
wire interface. It receives device address, operation code, wiper
register address and data from a 2-wire external master device
at the rising edge of the serial clock SCL, and it shifts out data
after each falling edge of the serial clock SCL.
SDA requires an external pull-up resistor, since it’s an open
drain output.
Serial Clock (SCL)
This input is the serial clock of the 2-wire and Up/Down
interface.
Device Address (A0, A1, A2)
The Address inputs are used to set the least significant 3 bits of
the 8-bit 2-wire interface slave address. A match in the slave
address serial data stream must be made with the Address input
pins in order to initiate communication with the X9252. A
maximum of 8 devices may occupy the 2-wire serial bus.
Chip Select (CS)
When the CS pin is low, increment or decrement operations
are possible using the SCL and U/D pins. The 2-wire interface
is disabled at this time. When CS is high, the 2-wire interface is
enabled.
Up or Down Control (U/D)
The U/D input pin is held HIGH during increment operations
and held LOW during decrement operations.
DCP Select (DS1 and DS0)
The DS1 and DS0 select one of the four DCPs for an Up/Down
interface operation.
Hardware Write Protect Input (WP)
When the WP pin is set low, “write” operations to nonvolatile
DCP Data Registers are disabled. This includes both 2-wire
interface nonvolatile “Write”, and Up/Down interface “Store”
operations.
DCP Pins
RH0, RL0, RH1, RL1, RH2, RL2, RH3, and RL3
These pins are equivalent to the terminal connections on
mechanical potentiometers. Since there are 4 DCPs, there is
one set of RH and RL for each DCP.
RW0, RW1, RW2, and RW3
The wiper pins are equivalent to the wiper terminal of
mechanical potentiometers. Since there are four DCPs, there
are 4 RW pins.
FN8167 Rev 3.00
July 24, 2014
Page 3 of 19
