Microchip Technology ARD00330 データシート

DS39979A-page 48

 2010 Microchip Technology Inc.

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 5-1.
These bits are used in software to determine the nature
of the Reset. 

Table 5-2 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.

  

Power-on Reset

0000h

1

1

1

0

0

0

0

RESET Instruction

0000h

0

u

u

u

u

u

u

Brown-out Reset

0000h

1

1

1

u

0

u

u

MCLR during power-managed 
Run modes

0000h

u

1

u

u

u

u

u

MCLR during power-managed 
Idle modes and Sleep mode

0000h

u

1

0

u

u

u

u

WDT time-out during full power 
or power-managed Run modes

0000h

u

0

u

u

u

u

u

MCLR during full power 
execution

0000h

u

u

u

u

u

u

u

Stack Full Reset (STVREN = 1)

0000h

u

u

u

u

u

1

u

Stack Underflow Reset 
(STVREN = 1)

0000h

u

u

u

u

u

u

1

Stack Underflow Error (not an 
actual Reset, STVREN = 0)

0000h

u

u

u

u

u

u

1

WDT time-out during 
power-managed Idle or Sleep 
modes

PC + 2

u

0

0

u

u

u

u

Interrupt exit from 
power-managed modes

PC + 2

u

u

0

u

u

u

u

Legend: u = unchanged
Note 1:

When the wake-up is due to an interrupt and the GIEH or GIEL bit is set, the PC is loaded with the 
interrupt vector (0008h or 0018h).