PIC16F84A datasheet(130/337 Pages) MICROCHIP

130 / 337 page

PIC16C6X

DS30234D-page 130

13.4.5

TIME-OUT SEQUENCE

On power-up the time-out sequence is as follows: First

a PWRT time-out is invoked after the POR time delay

has expired. Then OST is activated. The total time-out

will vary based on oscillator conﬁguration and the sta-

tus of the PWRT. For example, in RC mode, with the

PWRT disabled, there will be no time-out at all.

Figure 13-11, Figure 13-12, and Figure 13-13 depict

time-out sequences on power-up.

Since the time-outs occur from the POR pulse, if the

MCLR/VPP pin is kept low long enough, the time-outs

will expire. Then bringing the MCLR/VPP pin high will

begin execution immediately (Figure 13-14). This is

useful for testing purposes or to synchronize more than

one PIC16CXX device operating in parallel.

Table 13-10 and Table 13-11 show the reset conditions

for some special function registers, while Table 13-12

shows the reset conditions for all the registers.

13.4.6

POWER CONTROL/STATUS REGISTER

(PCON)

The Power Control/Status Register, PCON has up to

two bits, depending upon the device. Bit0 is not imple-

mented on the PIC16C62/64/65.

Bit0 is BOR (Brown-out Reset Status bit). BOR is

unknown on Power-on Reset. It must then be set by the

user and checked on subsequent resets to see if BOR

cleared, indicating that a brown-out has occurred. The

BOR status bit is a “Don’t Care” and is not necessarily

predictable if the Brown-out Reset circuitry is disabled

(by clearing bit BODEN in the Conﬁguration Word).

Bit1 is POR (Power-on Reset Status bit). It is cleared

on a Power-on Reset and unaffected otherwise. The

user must set this bit following a Power-on Reset.

Applicable Devices

61 62 62A R62 63 R63 64 64A R64 65 65A R65 66 67

TABLE 13-5:

TIME-OUT IN VARIOUS SITUATIONS, PIC16C61/62/64/65

TABLE 13-6:

TIME-OUT IN VARIOUS SITUATIONS,

PIC16C62A/R62/63/R63/64A/R64/65A/R65/66/67

TABLE 13-7:

STATUS BITS AND THEIR SIGNIFICANCE, PIC16C61

TABLE 13-8:

STATUS BITS AND THEIR SIGNIFICANCE, PIC16C62/64/65

Oscillator Conﬁguration

Power-up

Wake-up from SLEEP

PWRTE = 1

PWRTE = 0

XT, HS, LP

72 ms + 1024TOSC

1024TOSC

1024 TOSC

72 ms

—

Oscillator Conﬁguration

Power-up

Brown-out

Wake up from

SLEEP

PWRTE = 0

PWRTE = 1

XT, HS, LP

72 ms + 1024TOSC

1024TOSC

72 ms + 1024TOSC

1024 TOSC

72 ms

—

72 ms

—

Power-on Reset or MCLR reset during normal operation

WDT Reset

WDT Wake-up

MCLR reset during SLEEP or interrupt wake-up from SLEEP

POR

011

Power-on Reset

00x

Illegal, TO is set on a Power-on Reset

0x0

Illegal, PD is set on a Power-on Reset

101

WDT Reset

100

WDT Wake-up

1uu

MCLR reset during normal operation

110

MCLR reset during SLEEP or interrupt wake-up from SLEEP

Legend: x = unknown, u = unchanged

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