cat5241 Catalyst Semiconductor, cat5241 Datasheet - Page 8

• Manufacturer Part Number: cat5241
• Description: Quad Digitally Programmable Potentiometers Dpp? With 64 Taps And I?c Interface
• Manufacturer: Catalyst Semiconductor

CAT5241
INSTRUCTIONS AND REGISTER
DESCRIPTION
SLAVE ADDRESS BYTE
The first byte sent to the CAT5241 from the
master/processor is called the Slave/DPP Address
Byte. The most significant four bits of the slave
address are a device type identifier. These bits for the
CAT5241 are fixed at 0101[B] (refer to Table 1).
The next four bits, A3 - A0, are the internal slave
address and must match the physical device address
which is defined by the state of the A3 - A0 input pins
for the CAT5241 to successfully continue the com-
mand sequence. Only the device which slave address
matches the incoming device address sent by the
master executes the instruction. The A3 - A0 inputs
can be actively driven by CMOS input signals or tied
to V
Table 1. Identification Byte Format
Table 2. Instruction Byte Format
Doc. No. MD-2011 Rev. O
CC
or V
SS
.
(MSB)
(MSB)
ID3
0
I3
ID2
1
I2
Device Type
Identifier
Instruction
Opcode
ID1
I1
0
ID0
I0
1
8
INSTRUCTION BYTE
The next byte sent to the CAT5241 contains the
instruction and register pointer information. The four
most significant bits used provide the instruction
opcode I [3:0]. The P1 and P0 bits point to one of four
Wiper Control Registers. The least two significant bits,
R1 and R0, point to one of the four data registers of
each associated potentiometer. The format is shown
in Table 2.
Data Register Selection
A3
WCR/Pot Selection
P1
Data Register Selected
A2
DR0
DR1
DR2
DR3
Slave Address
P0
A1
R1
Data Register
Characteristics subject to change without notice
Selection
R1
(LSB)
0
0
1
1
(LSB)
A0
R0
© Catalyst Semiconductor, Inc.
R0
0
1
0
1