PIC18F2221_1 Datasheet, PDF (357/402 Pages) Microchip Technology – Enhanced Flash Microcontrollers with 10-Bit A/D and nanoWatt Technology

PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-8:
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
I/O pins
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
30
33
32
31
34
34
FIGURE 27-9:
BROWN-OUT RESET TIMING
VDD
VIRVST
Enable Internal
Reference Voltage
Internal Reference
Voltage Stable
BVDD
35
36
TABLE 27-10: 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)
2
—
—
μs
31
TWDT Watchdog Timer Time-out Period
(no postscaler)
3.56 4.19 4.82
ms
32
TOST Oscillation Start-up Timer Period 1024 TOSC — 1024 TOSC — TOSC = OSC1 period
33
TPWRT Power-up Timer Period
57
67
77
ms
34
TIOZ I/O High-Impedance from MCLR
Low or Watchdog Timer Reset
—
2
—
μs
35
TBOR Brown-out Reset Pulse Width
200
—
—
μs VDD ≤ BVDD (see D005)
36
TIRVST Time for Internal Reference
Voltage to become Stable
—
20
50
μs
37
TLVD High/Low-Voltage Detect Pulse Width 200
—
—
μs VDD ≤ VLVD
38
TCSD CPU Start-up Time
—
10
—
μs
39
TIOBST Time for INTOSC to Stabilize
—
1
—
μs
© 2009 Microchip Technology Inc.
DS39689F-page 357