Datasheet

2010-2014 Microchip Technology Inc. DS20005010F-page 25
MCP7940N
5.5 Output Configurations
The MCP7940N features Square Wave Clock Output,
Alarm Interrupt Output, and General Purpose Output
modes. All of the output functions are multiplexed onto
MFP according to Ta bl e 5- 7 .
Only the alarm interrupt outputs are available while
operating from the backup power supply. If none of the
output functions are being used, the MFP can safely be
left floating.
TABLE 5-7: MFP OUTPUT MODES
FIGURE 5-7: MFP OUTPUT BLOCK DIAGRAM
Note: The MFP is an open-drain output and
requires a pull-up resistor to V
CC (typically
10 k).
SQWEN ALM0EN ALM1EN Mode
000
General Purpose
Output
010
Alarm Interrupt
Output
001
011
1xx
Square Wave Clock
Output
X2
X1
ST
Oscillator
EXTOSC
Postscaler
MUX
32.768 kHz
8.192 kHz
4.096 kHz
1 Hz
SQWFS<1:0>
11
10
01
00
Digital
Trim
1
0
64 Hz
CRSTRIM
MFP
0
1
SQWEN
0
1
0
1
ALM1IF
ALM0IF
ALMPOL
MUX
ALM1EN,ALM0EN
11
10
01
00
OUT
MCP7940N