Datasheet
MCP454X/456X/464X/466X
DS22107B-page 52 2008-2013 Microchip Technology Inc.
6.2.7 GENERAL CALL
The General Call is a method that the “Master” device
can communicate with all other “Slave” devices. In a
Multi-Master application, the other Master devices are
operating in Slave mode. The General Call address
has two documented formats. These are shown in
Figure 6-11. We have added a MCP45XX/46XX format
in this figure as well.
This will allow customers to have multiple I
2
C Digital
Potentiometers on the bus and have them operate in a
synchronous fashion (analogous to the DAC Sync pin
functionality). If these MCP45XX/46XX 7-bit com-
mands conflict with other I
2
C devices on the bus, then
the customer will need two I
2
C busses and ensure that
the devices are on the correct bus for their desired
application functionality.
Dual Pot devices can not update both Pot0 and Pot1
from a single command. To address this, there are
General Call commands for the Wiper 0, Wiper 1, and
the TCON registers.
Table 6-3 shows the General Call Commands. Three
commands are specified by the I
2
C specification and
are not applicable to the MCP45XX/46XX (so com-
mand is Not Acknowledged) The MCP45XX/46XX
General Call Commands are Acknowledge. Any other
command is Not Acknowledged.
TABLE 6-3: GENERAL CALL COMMANDS
Note: Only one General Call command per issue
of the General Call control byte. Any addi-
tional General Call commands are ignored
and Not Acknowledged.
7-bit
Command
(1, 2, 3)
Comment
‘1000 00d’b Write Next Byte (Third Byte) to Volatile
Wiper 0 Register
‘1001 00d’b Write Next Byte (Third Byte) to Volatile
Wiper 1 Register
‘1100 00d’b Write Next Byte (Third Byte) to TCON
Register
‘1000 010’b
or
‘1000 011’b
Increment Wiper 0 Register
‘1001 010’b
or
‘1001 011’b
Increment Wiper 1 Register
‘1000 100’b
or
‘1000 101’b
Decrement Wiper 0 Register
‘1001 100’b
or
‘1001 101’b
Decrement Wiper 1 Register
Note 1: Any other code is Not Acknowledged.
These codes may be used by other
devices on the I
2
C bus.
2: The 7-bit command always appends a “0”
to form 8-bits. .
3: “d” is the D8 bit for the 9-bit write value.