PIC18F2331_10 Datasheet, PDF (51/392 Pages) Microchip Technology – 28/40/44-Pin Enhanced Flash Microcontrollers with nanoWatt Technology, High-Performance PWM and A/D

PIC18F2331/2431/4331/4431
5.6 Reset State of Registers
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state” depending on the type of Reset that occurred.
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal
operation.
Status bits from the RCON register (RI, TO, PD, POR
and BOR) are set or cleared differently in different
Reset situations, as indicated in Table 5-2. These bits
are used in software to determine the nature of the
Reset.
Table 5-3 describes the Reset states for all of the
Special Function Registers. These are categorized by
Power-on and Brown-out Resets, Master Clear and
WDT Resets, and WDT wake-ups.
FIGURE 5-3:
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD, VDD RISE < TPWRT)
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
TPWRT
TOST
FIGURE 5-4:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
PWRT TIME-OUT
OST TIME-OUT
INTERNAL RESET
TPWRT
TOST
 2010 Microchip Technology Inc.
DS39616D-page 51