PIC18F2455_07 Datasheet, PDF (385/430 Pages) Microchip Technology – 28/40/44-Pin, High Performance, Enhanced Flash, USB Microcontrollers with nanoWatt Technology

PIC18F2455/2550/4455/4550
FIGURE 28-7:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
VDD
MCLR
Internal
POR
PWRT
Time-out
Oscillator
Time-out
Internal
Reset
Watchdog
Timer
Reset
33
32
I/O pins
Note: Refer to Figure 28-4 for load conditions.
30
31
34
34
FIGURE 28-8:
BROWN-OUT RESET TIMING
VDD
VIRVST
Enable Internal
Reference Voltage
Internal Reference
Voltage Stable
BVDD
35
36
VBGAP = 1.2V
TABLE 28-12: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
No.
Symbol
Characteristic
Min Typ Max Units
Conditions
30
TmcL MCLR Pulse Width (low)
31
TWDT Watchdog Timer Time-out Period
(no postscaler)
32
TOST Oscillator Start-up Timer Period
33
TPWRT Power-up Timer Period
34
TIOZ I/O High-Impedance from MCLR
Low or Watchdog Timer Reset
35
TBOR Brown-out Reset Pulse Width
36
TIRVST Time for Internal Reference
Voltage to become Stable
37
TLVD Low-Voltage Detect Pulse Width
38
TCSD CPU Start-up Time
39
TIOBST Time for INTOSC to Stabilize
Legend: TBD = To Be Determined
2
—
—
—
4.00 TBD
1024 TOSC — 1024 TOSC
—
65.5 TBD
—
2
—
200
—
—
—
20
50
200
—
—
5
—
10
—
1
—
μs
ms
— TOSC = OSC1 period
ms
μs
μs VDD ≤ BVDD (see D005)
μs
μs VDD ≤ VLVD
μs
ms
© 2007 Microchip Technology Inc.
Preliminary
DS39632D-page 383