
2011-2012 Microchip Technology Inc.
Preliminary
DS70657E-page 121
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X, AND PIC24EPXXXGP/MC20X
6.0
RESETS
The Reset module combines all reset sources and
controls the device Master Reset Signal, SYSRST. The
following is a list of device Reset sources:
POR: Power-on Reset
BOR: Brown-out Reset
MCLR: Master Clear Pin Reset
SWR: RESET Instruction
WDTO: Watchdog Timer Reset
CM: Configuration Mismatch Reset
TRAPR: Trap Conflict Reset
IOPUWR: Illegal Condition Device Reset
- Illegal Opcode Reset
- Uninitialized W Register Reset
- Security Reset
A simplified block diagram of the Reset module is
Any active source of Reset will make the SYSRST sig-
nal active. On system Reset, some of the registers
associated with the CPU and peripherals are forced to
a known Reset state and some are unaffected.
All types of device Reset sets a corresponding status
bit in the RCON register to indicate the type of Reset
A POR clears all the bits, except for the POR and BOR
bits (RCON<1:0>), that are set. The user application
can set or clear any bit at any time during code
execution. The RCON bits only serve as status bits.
Setting a particular Reset status bit in software does
not cause a device Reset to occur.
The RCON register also has other bits associated with
the Watchdog Timer and device power-saving states.
The function of these bits is discussed in other sections
of this manual.
There are two types of Reset, a cold Reset and a warm
Reset. A cold Reset is the result of a POR or BOR and
the FNOSC Configuration bits in the FOSC device
Configuration register select the device clock source. A
warm Reset is the result of all other Resets including
the RESET instruction and the Current Oscillator Selec-
tion bits (COSC<2:0>) in the Oscillator Control register
(OSCCON<14:12>) select the clock source.
FIGURE 6-1:
RESET SYSTEM BLOCK DIAGRAM
Note 1: This data sheet summarizes the features
of
the
dsPIC33EPXXXGP50X,
dsPIC33EPXXXMC20X/50X,
and
PIC24EPXXXGP/MC20X
families
of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 8. “Reset”
(DS70602) of the “dsPIC33E/PIC24E
Family Reference Manual”, which is
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
this data sheet for device-specific register
and bit information.
Note:
Refer to the specific peripheral section or
this manual for register Reset states.
Note:
The status bits in the RCON register
should be cleared after they are read so
that the next RCON register value after a
device Reset is meaningful.
MCLR
VDD
Internal
Regulator
BOR
Sleep or Idle
RESET Instruction
WDT
Module
Glitch Filter
Trap Conflict
Illegal Opcode
Uninitialized W Register
SYSRST
VDD Rise
Detect
POR
Configuration Mismatch
Security Reset