MCP4431 Microchip Technology Inc., MCP4431 Datasheet - Page 55

• Manufacturer Part Number: MCP4431
• Description: 7/8-bit Volatile Quad Digital Pot With I 2c Interface
• Manufacturer: Microchip Technology Inc.

7.0
The MCP44XX’s I
this section. The I
commands are formatted.
The MCP44XX supports four basic commands. The
location accessed determines the commands that are
supported.
For the Volatile Wiper Registers, these commands are:
• Write Data
• Read Data
• Increment Data
• Decrement Data
For the TCON Register, these commands are:
• Write Data
• Read Data
These commands have formats for both a single
command or continuous commands. These commands
are shown in
Each command has two operational states. These
operational states are referred to as:
• Normal Serial Commands
• High-Voltage Serial Commands
TABLE 7-1:
Normal serial commands are those where the HVC pin
is driven to V
Commands, the HVC pin is driven to V
mode, there are four possible commands.
Table 7-2
memory location.
Table 7-3
commands and their interaction with other device
features.
 2010 Microchip Technology Inc.
Write Data
Read Data
Increment
Decrement
Note 1:
Note:
Operation
DEVICE COMMANDS
shows the supported commands for each
shows an overview of all the device
“n” indicates the number of times the
command operation is to be repeated.
High Voltage commands are supported for
compatibility with Non-Volatile devices in
the family.
Command
Table
IH
2
I
C command formats are specified in
2
2
or V
7-1.
Single
Continuous
Single
Random
Continuous
Single
Continuous
Single
Continuous
C COMMANDS
C protocol does not specify how
IL
Mode
. With High-Voltage Serial
# of Bit Clocks
18n + 11
18n + 11
9n + 11
9n + 11
IHH
29
29
48
20
20
(1)
. In each
7.1
The MCP44XX’s Command Byte has three fields: the
Address, the Command Operation, and 2 Data bits
(see
defined (D8).
The device memory is accessed when the Master
sends a proper Command Byte to select the desired
operation. The memory location getting accessed is
contained in the Command Byte’s AD3:AD0 bits. The
action desired is contained in the Command Byte’s
C1:C0 bits, see
desired memory location will be read, written,
Incremented (wiper setting +1) or Decremented (wiper
setting -1). The Increment and Decrement commands
are only valid on the volatile wiper registers, and in
High Voltage commands to enable/disable WiperLock
Technology and Software Write Protect.
If the Address bits and Command bits are not a valid
combination, then the MCP44XX will generate a Not
Acknowledge pulse to indicate the invalid combination.
The I
Condition to reset the MCP44XX’s I
D9 and D8 are the most significant bits for the digital
potentiometer’s wiper setting. The 8-bit devices utilize
D8 as their MSb while the 7-bit devices utilize D7 (from
the data byte) as their MSb.
FIGURE 7-1:
Figure
2
C Master device must then force a Start
Command Byte
A A
7-1). Currently only one of the data bits is
Memory Address
D
3
MCP4XXX
Figure
A
D
2
COMMAND BYTE
MCP443X/5X
D
A
1
Command Byte Format.
7-1. C1:C0 determines if the
D
A
0
Command Operation bits
C
1
10 = Decrement
11 = Read Data
00 = Write Data
01 = Increment
C
0
D
2
9
MSbits (Data)
C module.
DS22267A-page 55
D
8
A