MCP4024 MICROCHIP [Microchip Technology], MCP4024 Datasheet - Page 29

• Manufacturer Part Number: MCP4024
• Manufacturer: MICROCHIP [Microchip Technology]

5.0
5.1
The MCP4021/2/3/4 utilizes a simple 2-wire interface to
increment or decrement the digital potentiometer’s
wiper terminal (W), store the wiper setting in non-vola-
tile memory and turn the WiperLock technology feature
on or off. This interface uses the Chip Select (CS) pin,
while the U/D pin is the Up/Down input.
The Increment/Decrement protocol enables the device
to move one step at a time through the range of
possible resistance values. The wiper value is
initialized with the value stored in the internal EEPROM
upon power-up. A wiper value of 00h connects the
wiper to terminal B. A wiper value of 3Fh connects the
wiper to terminal A. Increment commands move the
wiper toward terminal A, but will not increment to a
value greater than 3Fh. Decrement commands move
the wiper toward terminal B, but will not decrement
below 00h.
Refer to Section 1.0 “Electrical Characteristics”,
AC/DC Electrical Characteristics table for detailed input
threshold and timing specifications.
Communication is unidirectional. Therefore, the value
of the current wiper setting cannot be read out of the
MCP402X device.
TABLE 5-1:
© 2006 Microchip Technology Inc.
Increment without Writing Wiper Setting to EEPROM
Increment with Writing Wiper Setting to EEPROM
Decrement without Writing Wiper Setting to EEPROM
Decrement with Writing Wiper Setting to EEPROM
Write Wiper Setting to EEPROM
High-Voltage Increment and Disable WiperLock Technology
High-Voltage Increment and Enable WiperLock Technology
High-Voltage Decrement and Disable WiperLock Technology
High-Voltage Decrement and Enable WiperLock Technology
Write Wiper Setting to EEPROM and Disable WiperLock
Technology
Write Wiper Setting to EEPROM and Enable WiperLock
Technology
Note 1:
SERIAL INTERFACE
Overview
This command will only complete if wiper is “unlocked” (WiperLock Technology is Disabled).
COMMANDS
Command Name
5.2
The MCP402X devices support 10 serial commands.
The commands can be grouped into the following
types:
• Serial Commands
• High-voltage Serial Commands
All the commands are shown in
The command type is determined by the voltage level
on the CS pin. The initial state that the CS pin must be
driven is V
can be driven are:
• V
• V
If the CS pin is driven from V
command is selected. If the CS pin is driven from V
V
High-voltage serial commands control the state of the
WiperLock technology. This is a unique feature, where
the user can determine whether or not to “lock” or
“unlock” the wiper state.
High-voltage serial commands increment/decrement
the wiper regardless of the status of the WiperLock
technology.
IHH
IL
IHH
EEPROM
, a high-voltage serial command is selected.
Value in
Saves
Wiper
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
—
—
Serial Commands
IH
. From V
MCP4021/2/3/4
Voltage
on CS
High
pin?
Yes
Yes
Yes
Yes
Yes
Yes
—
—
—
—
—
IH
, the two levels that the CS pin
”unlocked”
Command
“locked”/
unlocked
unlocked
unlocked
unlocked
unlocked
unlocked
unlocked
unlocked
Wiper is
locked
locked
locked
After
Table
IH
DS21945E-page 29
to
5-1.
V
“locked”?
IL
Wiper is
Works
Note 1
Note 1
Note 1
Note 1
Note 1
, a serial
when
Yes
Yes
Yes
Yes
Yes
Yes
IH
to