X9258 Datasheet, PDF (9/22 Pages) Xicor Inc. – Quad Digital Controlled Potentiometers (XDCP)

X9258
REGISTER DESCRIPTIONS
Data Registers, (8-Bit), Nonvolatile
WP7 WP6 WP5 WP4 WP3 WP2 WP1 WP0
NV NV NV NV NV NV NV NV
(MSB)
(LSB)
Four 8-bit Data Registers for each DCP. (sixteen 8-bit
registers in total).
– {D7~D0}: These bits are for general purpose not
volatile data storage or for storage of up to four
different wiper values. The contents of Data Register
0 are automatically moved to the wiper counter
register on power-up.
Wiper Counter Register, (8-Bit), Volatile
WP7 WP6 WP5 WP4 WP3 WP2 WP1 WP0
V
VVVVVV
V
(MSB)
(LSB)
One 8-bit Wiper Counter Register for each DCP. (Four
8-bit registers in total.)
– {D7~D0}: These bits specify the wiper position of the
respective DCP. The Wiper Counter Register is
loaded on power-up by the value in Data Register 0.
The contents of the WCR can be loaded from any of
the other Data Register or directly. The contents of
the WCR can be saved in a DR.
Instruction Format
Notes: (1) “MACK”/”SACK”: stands for the acknowledge sent by the master/slave.
(2) “A3 ~ A0”: stands for the device addresses sent by the master.
(3) “X”: indicates that it is a “0” for testing purpose but physically it is a “don’t care” condition.
(4) “I”: stands for the increment operation, SDA held high during active SCL phase (high).
(5) “D”: stands for the decrement operation, SDA held low during active SCL phase (high).
Read Wiper Counter Register (WCR)
S device type
T identifier
device
addresses
S
instruction
opcode
WCR
addresses
S
wiper position
(sent by slave on SDA)
MS
A
R
T
0
1
0
1
A
3
A
2
A
1
A
0
A
C
K
1
0
0
1
0
0
P
1
P
0
A
AT
C ^WWWWWWWWC O
K
P
7
P
6
P
5
P
4
P
3
P
2
P
1
P
0
K
P
Write Wiper Counter Register (WCR)
S
T
A
R
T
device type
identifier
0101
device
addresses
AAAA
3210
S
A
C
K
instruction
opcode
1010
WCR
addresses
0
0
P
1
P
0
S
A
Data Byte
(sent by master on SDA)
S
A
S
T
C ^WWWWWWWWC O
K
P
7
P
6
P
5
P
4
P
3
P
2
P
1
P
0
K
P
Read Data Register (DR)
S
T
A
R
T
device type
identifier
0101
device
addresses
AAAA
3210
S
A
C
K
instruction
opcode
1011
DR and WCR
addresses
RRPP
1010
S
A
Data Byte
(sent by slave on SDA)
MS
AT
C ^WWWWWWWWC O
K
P
7
P
6
P
5
P
4
P
3
P
2
P
1
P
0
K
P
REV 1.1.7 2/4/03
www.xicor.com
Characteristics subject to change without notice. 9 of 22