PIC16F627-04 Microchip Technology, PIC16F627-04 Datasheet - Page 102

• Manufacturer Part Number: PIC16F627-04
• Description: FLASH-Based 8-Bit CMOS Microcontrollers
• Manufacturer: Microchip Technology

PIC16F62X
14.5.5
On power-up the time-out sequence is as follows: First
PWRT time-out is invoked after POR has expired. Then
OST is activated. The total time-out will vary based on
oscillator configuration and PWRTE bit status. For
example, in ER mode with PWRTE bit erased (PWRT
disabled), there will be no time-out at all. Figure 14-10,
Figure 14-11
sequences.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, the time-outs will expire. Then
bringing MCLR high will begin execution immediately
(see Figure 14-11). This is useful for testing purposes
or to synchronize more than one PIC16F62X device
operating in parallel.
Table 14-6 shows the reset conditions for some special
registers, while Table 14-7 shows the reset conditions
for all the registers.
TABLE 14-3:
TABLE 14-4:
Legend: u = unchanged, x = unknown
TABLE 14-5:
DS40300B-page 102
Address Name
Oscillator Configuration
03h
8Eh
Note 1:
POR
1
0
0
0
1
1
1
1
TIME-OUT SEQUENCE
STATUS
XT, HS, LP
PCON
Other (non power-up) resets include MCLR reset, Brown-out Detect and Watchdog Timer Reset during normal operation.
ER
BOD
and
X
X
X
0
1
1
1
1
TIME-OUT IN VARIOUS SITUATIONS
STATUS/PCON BITS AND THEIR SIGNIFICANCE
SUMMARY OF REGISTERS ASSOCIATED WITH BROWN-OUT
Bit 7
IRP
—
Figure 14-12
TO
1
0
X
X
0
0
u
1
Bit 6
RP1
—
72 ms + 1024 T
PWRTE = 0
PD
depict
1
X
0
X
u
0
u
0
Bit 5
RPO
72 ms
—
time-out
OSC
Bit 4
Power-up
TO
—
Preliminary
OSCF
Bit 3
PD
PWRTE = 1
1024 T
14.5.6
The power control/status register, PCON (address
8Eh) has two bits.
Bit0 is BOD (Brown-out). BOD is unknown on
power-on-reset. It must then be set by the user and
checked on subsequent resets to see if BOD = 0
indicating that a brown-out has occurred. The BOD
status bit is a don’t care and is not necessarily
predictable if the brown-out circuit is disabled (by
setting BODEN bit = 0 in the Configuration word).
Bit1 is POR (Power-on-reset). It is a ‘0’ on
power-on-reset and unaffected otherwise. The user
must write a ‘1’ to this bit following a power-on-reset.
On a subsequent reset if POR is ‘0’, it will indicate that
a power-on-reset must have occurred (V
gone too low).
—
MCLR reset during normal operation
OSC
Bit 2
—
Z
MCLR reset during SLEEP
Illegal, PD is set on POR
Illegal, TO is set on POR
POWER CONTROL (PCON)/
STATUS REGISTER
Brown-out Detect
Power-on-reset
WDT Wake-up
Bit 1
POR
WDT Reset
DC
Brown-out Reset
72 ms + 1024 T
Bit 0
BOD
C
72 ms
1999 Microchip Technology Inc.
Value on POR
0001 1xxx
---- 1-0x
OSC
Reset
from SLEEP
DD
1024 T
Wake-up
other resets
Value on all
000q quuu
---- u-uq
may have
—
OSC
(1)