X9410 Xicor, X9410 Datasheet - Page 5

• Manufacturer Part Number: X9410
• Description: Dual Digitally Controlled Potentiometer
• Manufacturer: Xicor

X9410
Figure 3. Instruction Byte Format
The four high order bits of the instruction byte specify
the operation. The next two bits (R
of the four registers that is to be acted upon when a
register oriented instruction is issued. The last bit (P
selects which one of the two potentiometers is to be
affected by the instruction.
Four of the ten instructions are two bytes in length and
end with the transmission of the instruction byte. These
instructions are:
– XFR Data Register to Wiper Counter Register—This
– XFR Wiper Counter Register to Data Register—This
– Global XFR Data Register to Counter Register—This
– Global XFR Wiper Counter Register to Data Register—
The basic sequence of the two byte instructions is
illustrated in Figure 4. These two-byte instructions
exchange data between the WCR and one of the data
registers. A transfer from a Data Register to a WCR is
essentially a write to a static RAM, with the static RAM
controlling the wiper position. The response of the
wiper to this action will be delayed by t
from the WCR (current wiper position), to a data register
REV 1.1 10/6/00
transfers the contents of one specified Data Register
to the associated Wiper Counter Register.
transfers the contents of the specified Wiper Counter
Register to the specified associated Data Register.
transfers the contents of both specified Data Registers
to the associated Wiper Counter Registers.
This transfers the contents of both Wiper Counter
Registers to the specified associated Data Registers.
I3
Instructions
I2
I1
I0
Register
R1
Select
R0
1
and R
0
WRL
Pot Select
0
) select one
P0
. A transfer
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0
)
is a write to nonvolatile memory and takes a minimum
of t
one of the two potentiometers and one of its associated
registers; or it may occur globally, where the transfer
occurs
associated register.
Five instructions require a three-byte sequence to
complete. These instructions transfer data between the
host and the X9410; either between the host and one
of the data registers or directly between the host and
the Wiper Counter Register. These instructions are:
– Read Wiper Counter Register—read the current
– Write Wiper Counter Register—change current wiper
– Read Data Register—read the contents of the
– Write Data Register—write a new value to the
– Read Status—This command returns the contents of
The sequence of these operations is shown in Figure 5
and Figure 6.
The final command is Increment/Decrement. It is
different from the other commands because it’s length
is indeterminate. Once the command is issued, the
master can clock the selected wiper up and/or down in
one resistor segment steps, thereby providing a fine
tuning capability to the host. For each SCK clock pulse
(t
one resistor segment towards the V
Similarly, for each SCK clock pulse while SI is LOW, the
selected wiper will move one resistor segment towards
the V
sequence and timing for this operation are shown in
Figures 7-8.
HIGH
wiper position of the selected pot,
position of the selected pot,
selected data register;
selected data register.
the WIP bit which indicates if the internal write cycle
is in progress.
WR
) while SI is HIGH, the selected wiper will move
L
/R
to complete. The transfer can occur between
between
L
terminal. A detailed illustration of the
Characteristics subject to change without notice.
both
potentiometers
H
/R
H
and
terminal.
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one