Datasheet

PIC16F527
DS41652A-page 52 Preliminary  2012 Microchip Technology Inc.
8.9 Brown-out Reset (BOR)
A brown-out is a condition where device power (VDD)
dips below its minimum value, but not to zero, and
then recovers. The device should be reset in the event
of a brown-out. The Brown-out Reset feature is
enabled by the BOREN Configuration bit.
If V
DD falls below VBOR for greater than parameter
(T
BOR) (see Figure 8-12), the brown-out situation will
reset the device. This will occur regardless of V
DD slew
rate. A Reset is not insured to occur if V
DD falls below
V
BOR for less than parameter (TBOR).
On any Reset (Power-on, Brown-out Reset, Watchdog
Timer, etc.), the chip will remain in Reset until V
DD rises
above V
BOR (see Figure 8-12). If enabled, the Device
Reset Timer will now be invoked, and will keep the chip
in Reset an additional 18 ms.
If V
DD drops below VBOR while the Device Reset Timer
is running, the chip will go back into a Brown-out Reset
and the Device Reset Timer will be re-initialized. Once
V
DD rises above VBOR, the Device Reset Timer will
execute a 18 ms Reset.
FIGURE 8-12: BROWN-OUT RESET TIMING AND CHARACTERISTICS
FIGURE 8-13: BROWN-OUT SITUATIONS
Note: The Device Reset Timer is enabled by the
DRTEN bit in the Configuration Word
register.
VBOR
VDD
(Device in Brown-out Reset) (Device not in Brown-out Reset)
32
37
Reset
(due to BOR)
V
BOR + VHYST
18 ms
V
BOR
V
DD
Internal
Reset
VBOR
V
DD
Internal
Reset
18 ms
< 18 ms
18 ms
V
BOR
V
DD
Internal
Reset
(DRTEN = 1)
(DRTEN = 1)
(DRTEN = 1)