PIC16F877-20L Datasheet, PDF (164/218 Pages) Microchip Technology – 28/40-Pin 8-Bit CMOS FLASH Microcontrollers

PIC16F87X
FIGURE 15-8:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
33
32
I/O Pins
Note: Refer to Figure 15-5 for load conditions.
30
31
34
34
FIGURE 15-9:
BROWN-OUT RESET TIMING
VDD
VBOR
35
TABLE 15-3: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER,
AND BROWN-OUT RESET REQUIREMENTS
Parameter
No.
Symbol
Characteristic
Min
Typ†
Max Units
Conditions
30
TmcL MCLR Pulse Width (low)
2
—
—
s VDD = 5V, -40°C to +85°C
31*
Twdt Watchdog Timer Time-out Period
7
18
33
ms VDD = 5V, -40°C to +85°C
(No Prescaler)
32
Tost Oscillation Start-up Timer Period
— 1024 TOSC —
— TOSC = OSC1 period
33*
Tpwrt Power-up Timer Period
28
72
132 ms VDD = 5V, -40°C to +85°C
34
TIOZ I/O Hi-impedance from MCLR Low —
—
2.1 s
or Watchdog Timer Reset
35
TBOR Brown-out Reset pulse width
100
—
—
s VDD  VBOR (D005)
* These parameters are characterized but not tested.
† Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
DS30292D-page 164
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