Datasheet

 2008-2013 Microchip Technology Inc. DS22096B-page 59
MCP453X/455X/463X/465X
7.6 Increment Wiper
Normal and High Voltage
The Increment Command provides a quick and easy
method to modify the potentiometer’s wiper by +1 with
minimal overhead. The Increment Command will only
function on the volatile wiper setting memory locations
00h and 01h.
When executing an Increment Command, the volatile
wiper setting will be altered from n to n+1 for each
Increment Command received. The value will incre-
ment up to 100h maximum on 8-bit devices, and 80h on
7-bit devices. If multiple Increment Commands are
received after the value has reached 100h (or 80h), the
value will not be incremented further. Table 7-4 shows
the Increment Command versus the current volatile
wiper value.
Refer to Figure 7-7 for the Increment Command
sequence. The sequence is terminated by the Stop
condition. So when executing a continuous command
string, the Increment command can be followed by any
other valid command. This means that writes do not
need to be to the same volatile memory address.
The advantage of using an Increment Command
instead of a read-modify-write series of commands is
speed and simplicity. The wiper will transition after
each Command Acknowledge when accessing the vol-
atile wiper registers.
TABLE 7-4: INCREMENT OPERATION VS.
VOLATILE WIPER VALUE
7.6.1 THE HIGH VOLTAGE COMMAND
(HVC) SIGNAL
The High Voltage Command (HVC) signal is multi-
plexed with Address 0 (A0) and is used to indicate that
the command, or sequence of commands, are in the
High Voltage mode. An HVC/A0 pin voltage > V
IHH
(~8.5V) puts the MCP45XX/46XX device into the High
Voltage mode.
The HVC pin has an internal resistor connection to the
MCP45XX/46XXs internal V
DD
signal.
FIGURE 7-7: I
2
C Increment Command Sequence.
Note: Table 7-2 shows the valid addresses for
the Increment Wiper command. Other
addresses are invalid.
Note: The command sequence can go from an
increment to any other valid command for
the specified address.
Current Wiper
Setting
Wiper (W)
Properties
Increment
Command
Operates?
7-bit
Pot
8-bit
Pot
3FFh
081h
3FFh
101h
Reserved
(Full-Scale (W = A))
No
080h 100h Full-Scale (W = A) No
07Fh
041h
0FFh
081
W = N
040h 080h W = N (Mid-Scale) Yes
03Fh
001h
07Fh
001
W = N
000h 000h Zero Scale (W = B) Yes
Note: There is a required delay after the HVC pin
is driven to the V
IHH
level to the 1st edge
of the SCL pin.
Control Byte
INCR Command (n+1) INCR Command (n+2)
1010SA2A1A00 0
AD
AD
AD
AD
A1xXA0
AD AD AD AD
1x XAP
(2)
0
1
2
3
4321
Fixed
Address
Variable
Address
Device
Memory
Address
Command
Write bit
Note1: Increment Command (INCR) only functions when accessing the volatile wiper
registers (AD3:AD0 = 0h and 1h).
2: This command sequence does not need to terminate (using the Stop bit) and can
change to any other desired command sequence (Increment, Read or Write).