
2010-2012 Microchip Technology Inc.
DS41417B-page 27
PIC16(L)F722A/723A
3.0
RESETS
The PIC16(L)F722A/723A differentiates between
various kinds of Reset:
a)
Power-on Reset (POR)
b)
WDT Reset during normal operation
c)
WDT Reset during Sleep
d)
MCLR Reset during normal operation
e)
MCLR Reset during Sleep
f)
Brown-out Reset (BOR)
Some registers are not affected in any Reset condition;
their status is unknown on POR and unchanged in any
other Reset. Most other registers are reset to a “Reset
state” on:
Power-on Reset (POR)
MCLR Reset
MCLR Reset during Sleep
WDT Reset
Brown-out Reset (BOR)
Most registers are not affected by a WDT wake-up
since this is viewed as the resumption of normal
operation. TO and PD bits are set or cleared differently
in different Reset situations, as indicated in
Table 3-3.These bits are used in software to determine the nature
of the Reset.
A simplified block diagram of the On-Chip Reset Circuit
The MCLR Reset path has a noise filter to detect and
FIGURE 3-1:
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
MCLR/VPP
VDD
OSC1/
WDT
Module
POR
OST/PWRT
WDTOSC
WDT
Time-out
Power-on Reset
OST
10-bit Ripple Counter
PWRT
Chip_Reset
11-bit Ripple Counter
Reset
Enable OST
Enable PWRT
Sleep
Brown-out(1)
Reset
BOREN
CLKIN
Note 1:
MCLRE