X9313
The wiper, when at either fixed terminal, acts like its
mechanical equivalent and does not move beyond the last
position. That is, the counter does not wrap around when
clocked to either extreme.
Chip Select (CS)
The device is selected when the CS input is LOW. The current
counter value is stored in nonvolatile memory when CS is
returned HIGH while the INC input is also HIGH. After the store
operation is complete, the X9313 will be placed in the low power
standby mode until the device is selected once again.
The electronic switches on the device operate in a “make
before break” mode when the wiper changes tap positions. If
the wiper is moved several positions, multiple taps are
Pinouts
connected to the wiper for t (INC to V change). The
IW
W
X9313
(8 LD PDIP, 8 LD SOIC)
TOP VIEW
R
value for the device can temporarily be reduced by a
TOTAL
significant amount if the wiper is moved several positions.
When the device is powered-down, the last wiper position
stored will be maintained in the nonvolatile memory. When
power is restored, the contents of the memory are recalled and
the wiper is set to the value last stored.
INC
1
2
3
4
8
7
6
5
VCC
U/D
RH/VH
VSS
CS
X9313
RL/VL
RW/VW
Instructions and Programming
The INC, U/D and CS inputs control the movement of the wiper
along the resistor array. With CS set LOW the device is
selected and enabled to respond to the U/D and INC inputs.
HIGH to LOW transitions on INC will increment or decrement
(depending on the state of the U/D input) a seven bit counter.
The output of this counter is decoded to select one of thirty-two
wiper positions along the resistive array.
X9313
(8 LD MSOP)
TOP VIEW
RH/VH
U/D
INC
VCC
1
8
7
6
5
VSS
RW/VW
RL/VL
2
3
4
X9313
The value of the counter is stored in nonvolatile memory
whenever CS transitions HIGH while the INC input is also
HIGH.
CS
The system may select the X9313, move the wiper and
deselect the device without having to store the latest wiper
position in nonvolatile memory. After the wiper movement is
performed as previously described and once the new position
is reached, the system must keep INC LOW while taking CS
HIGH. The new wiper position will be maintained until changed
by the system or until a power-up/down cycle recalled the
previously stored data.
TABLE 1. PIN NAMES
DESCRIPTION
High terminal
SYMBOL
RH/VH
RW/VW
RL/VL
VSS
Wiper terminal
Low terminal
Ground
This procedure allows the system to always power-up to a
preset value stored in nonvolatile memory; then during system
operation, minor adjustments could be made. The adjustments
might be based on user preference, system parameter
changes due to temperature drift, etc.
VCC
Supply voltage
U/D
Up/Down control input
Increment control input
Chip Select control input
INC
CS
The state of U/D may be changed while CS remains LOW. This
allows the host system to enable the device and then move the
wiper up and down until the proper trim is attained.
Principles of Operation
There are three sections of the X9313: the input control,
counter and decode section; the nonvolatile memory; and the
resistor array. The input control section operates just like an
up/down counter. The output of this counter is decoded to turn
on a single electronic switch connecting a point on the resistor
array to the wiper output. Under the proper conditions, the
contents of the counter can be stored in nonvolatile memory
and retained for future use. The resistor array is comprised of
31 individual resistors connected in series. At either end of the
array and between each resistor is an electronic switch that
transfers the potential at that point to the wiper.
TABLE 2. MODE SELECTION
CS
INC
U/D
MODE
L
H
Wiper up
L
L
Wiper down
H
X
Store wiper position
H
X
L
X
X
Standby current
No store, return to standby
FN8177 Rev 7.00
October 7, 2015
Page 3 of 12
RENESAS [ RENESAS TECHNOLOGY CORP ]
