CAT5269_13 Datasheet, PDF (10/15 Pages) ON Semiconductor – Dual Digital Potentiometer (POT)

CAT5269
Data Registers (DR)
Each potentiometer has four 8-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 10 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 13. INSTRUCTION SET
Instruction Set
Instruction
WCR1/
I3 I2 I1 I0 R1 R0
P1
Read Wiper Control
1001 0
0
1/0
Register
Write Wiper Control
1010 0
0
1/0
Register
Read Data Register
1 0 1 1 1/0 1/0
1/0
Write Data Register
1 1 0 0 1/0 1/0
1/0
XFR Data Register to 1 1 0 1 1/0 1/0
1/0
Wiper Control
Register
XFR Wiper Control
Register to Data
Register
1 1 1 0 1/0 1/0
1/0
Gang XFR Data
0 0 0 1 1/0 1/0
0
Registers to Wiper
Control Registers
Gang XFR Wiper
1 0 0 0 1/0 1/0
0
Control Registers to
Data Register
Increment/Decrement 0 0 1 0 0
0
1/0
Wiper Control Register
NOTE: 1/0 = data is one or zero
WCR0/
P0
1/0
1/0
1/0
1/0
1/0
1/0
0
0
1/0
Operation
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 both 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 both pots
Enable Increment/decrement of the Control
Latch pointed to by P1−P0
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 t_WR.
A transfer from the WCR (current wiper position), to a Data
Register is a write to non-volatile memory and takes a
minimum of t_WR to complete. The transfer can occur
between one of the two potentiometers and one of its
associated registers; or the transfer can occur between both
potentiometers and one associated register.
Four instructions require a two-byte sequence to
complete, as illustrated in Figure 10. These instructions
transfer data between the host/processor and the CAT5269;
either between the host and one of the data registers or
directly between the host and the Wiper Control Register.
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