Datasheet

PIC10F200/202/204/206
DS40001239E-page 48  2004-2013 Microchip Technology Inc.
9.7 Time-out Sequence, Power-down
and Wake-up from Sleep Status
Bits (TO
, PD, GPWUF, CWUF)
The TO, PD, GPWUF and CWUF bits in the STATUS
register can be tested to determine if a Reset condition
has been caused by a power-up condition, a MCLR,
Watchdog Timer (WDT) Reset, wake-up on comparator
change or wake-up on pin change.
TABLE 9-5: TO, PD, GPWUF, CWUF STATUS AFTER RESET
9.8 Reset on Brown-out
A Brown-out Reset is a condition where device power
(V
DD) dips below its minimum value, but not to zero,
and then recovers. The device should be reset in the
event of a brown-out.
To reset PIC10F200/202/204/206 devices when a
Brown-out Reset occurs, external brown-out protection
circuits may be built, as shown in Figure 9-7 and
Figure 9-8.
FIGURE 9-7: BROWN-OUT
PROTECTION CIRCUIT 1
FIGURE 9-8: BROWN-OUT
PROTECTION CIRCUIT 2
CWUF GPWUF TO PD Reset Caused By
0000WDT wake-up from Sleep
000uWDT time-out (not from Sleep)
0010MCLR
wake-up from Sleep
0011Power-up
00uuMCLR
not during Sleep
0110Wake-up from Sleep on pin change
1010Wake-up from Sleep on comparator change
Legend: u = unchanged, x = unknown, – = unimplemented bit, read as ‘0’, q = value depends on condition.
Note 1: The TO, PD, GPWUF and CWUF bits maintain their status (u) until a Reset occurs. A low-pulse on the
MCLR
input does not change the TO, PD, GPWUF or CWUF Status bits.
Note 1: This circuit will activate Reset when VDD goes
below Vz + 0.7V (where Vz = Zener voltage).
2: Pin must be confirmed as MCLR
.
33k
10k
40k
(1)
VDD
MCLR
(2)
PIC10F20X
VDD
Q1
Note 1: This brown-out circuit is less expensive,
although less accurate. Transistor Q1 turns
off when V
DD is below a certain level such
that:
2: Pin must be confirmed as MCLR
.
V
DD •
R1
R1 + R2
= 0.7V
R2
40k
(1)
VDD
MCLR
(2)
PIC10F20X
R1
Q1
VDD