Datasheet

© 2007 Microchip Technology Inc. DS41213D-page 23
PIC16F5X
5.0 RESET
The PIC16F5X devices may be reset in one of the
following ways:
• Power-on Reset (POR)
•MCLR
Reset (normal operation)
•MCLR Wake-up Reset (from Sleep)
• WDT Reset (normal operation)
• WDT Wake-up Reset (from Sleep)
Table 5-1 shows these Reset conditions for the PCL
and STATUS registers.
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
or WDT
Reset. A MCLR
or WDT wake-up from Sleep also
results in a device Reset and not a continuation of
operation before Sleep.
The TO
and PD bits (STATUS <4:3>) are set or cleared
depending on the different Reset conditions (Table 5-1).
These bits may be used to determine the nature of the
Reset.
Table 5-3 lists a full description of Reset states of all
registers. Figure 5-1 shows a simplified block diagram
of the on-chip Reset circuit.
TABLE 5-1: STATUS BITS AND THEIR SIGNIFICANCE
TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH RESET
Condition TO PD
Power-on Reset 11
MCLR
Reset (normal operation) uu
MCLR
Wake-up (from Sleep) 10
WDT Reset (normal operation) 01
WDT Wake-up (from Sleep) 00
Legend: u = unchanged, x = unknown, — = unimplemented read as ‘0’.
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Value on
POR
Value on
MCLR
and
WDT Reset
03h STATUS
PA2 PA1 PA0 TO PD Z DC C 0001 1xxx 000q quuu
Legend: u = unchanged, x = unknown, q = see Table 5-1 for possible values.