PIC16F872 Datasheet, PDF (134/160 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS FLASH Microcontroller

PIC16F872
FIGURE 14-6: 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
I/O Pins
33
32
30
31
34
34
Note: Refer to Figure 14-3 for load conditions.
FIGURE 14-7: BROWN-OUT RESET TIMING
VDD
VBOR
35
TABLE 14-3: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER,
AND BROWN-OUT RESET REQUIREMENTS
Parameter Sym Characteristic
No.
Min Typ† Max Units
Conditions
30
TmcL MCLR Pulse Width (low)
2
—
—
µs 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
35
Legend: *
†
TIOZ
I/O Hi-impedance from MCLR Low —
—
2.1
µs
or Watchdog Timer Reset
TBOR Brown-out Reset pulse width
100
—
—
µs 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.
DS30221A-page 134
Preliminary
© 1999 Microchip Technology Inc.