cat5411 Catalyst Semiconductor, cat5411 Datasheet - Page 9

• Manufacturer Part Number: cat5411
• Description: Dual Digitally Programmable Potentiometers Dpp? With 64 Taps And Spi Interface
• Manufacturer: Catalyst Semiconductor

WIPER CONTROL AND DATA REGISTERS
Wiper Control Register (WCR)
The CAT5411 contains two 6-bit Wiper Control
Registers, one for each potentiometer. The Wiper
Control Register output is decoded to select one of 64
switches along its resistor array. The contents of the
WCR can be altered in four ways: it may be written by
the host via Write Wiper Control Register instruction; it
may be written by transferring the contents of one of
four associated Data Registers via the XFR Data
Register instruction, it can be modified one step at a
time by the Increment/decrement instruction (see
Instruction section for more details). Finally, it is
loaded with the content of its data register zero (DR0)
upon power-up.
The Wiper Control Register is a volatile register that
loses its contents when the CAT5411 is powered-
down. Although the register is automatically loaded
with the value in DR0 upon power-up, this may be
different from the value present at power-down.
Data Registers (DR)
Each potentiometer has four 6-bit non-volatile Data
Registers. These can be read or written directly by the
host. Data can also be transferred between any of the
four Data Registers and the associated Wiper Control
Register. Any data changes in one of the Data
Registers is a non-volatile operation and will take a
maximum of 5ms.
Table 3. Instruction Set
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Instruction
Read Wiper Control Register 1
Write Wiper Control Register 1
Read Data Register
Write Data Register
XFR Data Register to Wiper
Control Register
XFR Wiper Control Register
to Data Register
Global XFR Data Registers
to Wiper Control Registers
Global XFR Wiper Control
Registers to Data Register
Increment/Decrement Wiper
Control Register
Read Status
I3
1
1
1
1
0
1
0
0
I2
0
0
0
1
1
1
0
0
0
1
I1
0
1
1
0
0
1
0
0
1
0
Instruction Set
I0
1
1 1/0 1/0
0 1/0 1/0
1 1/0 1/0
0 1/0 1/0
1 1/0 1/0
0 1/0 1/0
0
1
0
R1
0
0
0
0
R0
0
0
0
0
9
0
0
0
0
0
0
0
0
0
0
0
Write in Process
The contents of the Data Registers are saved to
nonvolatile memory when the CS
after a write sequence is received. The status of the
internal write cycle can be monitored by issuing a
Read Status command to read the Write in Process
(WIP) bit.
INSTRUCTIONS
Four of the ten instructions are three bytes in length.
These instructions are:
— Read Wiper Control Register – read the current
— Write Wiper Control Register – change current
— Read Data Register – read the contents of the
— Write Data Register – write a new value to the
— Read Status – Read the status of the WIP bit
WCR
wiper position of the selected potentiometer in
the WCR
wiper position in the WCR of the selected
potentiometer
selected Data Register
selected Data Register
which when set to "1" signifies a write cycle is in
progress.
1/0
1/0
1/0
1/0
1/0
1/0
1/0
0
0
1
0
/ P0
Operations
Read the contents of the Wiper Control Register
pointed to by P1-P0
Write new value to the Wiper Control Register
pointed to by P1-P0
Read the contents of the Data Register pointed to by
P1-P0 and R1-R0
Write new value to the Data Register pointed to by
P1-P0 and R1-R0
Transfer the contents of the Data Register pointed to
by P1-P0 and R1-R0 to its associated Wiper Control
Register
Transfer the contents of the Wiper Control Register
pointed to by P1-P0 to the Data Register pointed to
by R1-R0
Transfer the contents of the Data Registers pointed to
by R1-R0 of all four pots to their respective Wiper
Control Registers
Transfer the contents of both Wiper Control Registers
to their respective data Registers pointed to by
R1-R0 of all four pots
Enable Increment/decrement of the Control Latch
pointed to by P1-P0
Read WIP bit to check internal write cycle status
Note: 1/0 = data is one or zero
¯¯¯ input goes HIGH
Doc. No. MD-2114 Rev. I
CAT5411