CAT5221(2013) 데이터 시트보기 (PDF) - ON Semiconductor
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CAT5221 Datasheet PDF : 15 Pages
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CAT5221
WIPER CONTROL AND DATA REGISTERS
Wiper Control Register (WCR)
The CAT5221 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 CAT5221 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 5 ms.
If the application does not require storage of multiple
settings for the potentiometer, the Data Registers can be used
as standard memory locations for system parameters or user
preference data.
Instructions
Four of the nine instructions are three bytes in length.
These instructions are:
Read Wiper Control Register – read the current
wiper position of the selected potentiometer in the
WCR
Write Wiper Control Register – change current
wiper position in the WCR of the selected
potentiometer
Read Data Register – read the contents of the
selected Data Register
Write Data Register – write a new value to the
selected Data Register
Table 12. INSTRUCTION SET
Instruction Set
Instruction
WCR0/
I3 I2 I1 I0 0
P0
R1 R0
Operation
Read Wiper Control Register 1 0 0 1 0
1/0
0 0 Read the contents of the Wiper Control Register
pointed to by P0
Write Wiper Control Register 1 0 1 0 0
1/0
0 0 Write new value to the Wiper Control Register
pointed to by P0
Read Data Register
10110
1/0
1/0 1/0 Read the contents of the Data Register pointed to by
P0 and R1−R0
Write Data Register
11000
1/0
1/0 1/0 Write new value to the Data Register pointed to by
P0 and R1−R0
XFR Data Register to Wiper 1 1 0 1 0
1/0
1/0 1/0 Transfer the contents of the Data Register pointed to
Control Register
by P0 and R1−R0 to its associated Wiper Control
Register
XFR Wiper Control Register 1 1 1 0 0
1/0
1/0 1/0 Transfer the contents of the Wiper Control Register
to Data Register
pointed to by P0 to the Data Register pointed to by
R1−R0
Global XFR Data Registers
00010
0
1/0 1/0 Transfer the contents of the Data Registers pointed
to Wiper Control Registers
to by R1−R0 of all four pots to their respective Wiper
Control Registers
Global XFR Wiper Control
10000
0
1/0 1/0 Transfer the contents of both Wiper Control
Registers to Data Register
Registers to their respective data Registers pointed
to by R1−R0 of all four pots
Increment/Decrement Wiper 0 0 1 0 0
1/0
Control Register
0 0 Enable Increment/decrement of the Control Latch
pointed to by P0
NOTE: 1/0 = data is one or zero
The basic sequence of the three byte instructions is
illustrated in Figure 11. These three-byte instructions
exchange data between the WCR and one of the Data
Registers. The WCR controls the position of the wiper. The
response of the wiper to this action will be delayed by tWRL.
A transfer from the WCR (current wiper position), to a Data
Register is a write to non-volatile memory and takes a
maximum of tWR to complete. The transfer can occur
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