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PIC18F2450_08 Datasheet, PDF (290/324 Pages) Microchip Technology – 28/40/44-Pin, High-Performance, 12 MIPS, Enhanced Flash, USB Microcontrollers with nanoWatt Technology | |||
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PIC18F2450/4450
FIGURE 21-7:
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 21-4 for load conditions.
30
31
34
34
FIGURE 21-8:
BROWN-OUT RESET TIMING
VDD
VIRVST
Enable Internal
Reference Voltage
Internal Reference
Voltage Stable
BVDD
35
36
VBGAP = 1.2V
TABLE 21-10: 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
â
â
μs
31
TWDT Watchdog Timer Time-out Period
(no postscaler)
â
4.00
4.6
ms
32
TOST Oscillator Start-up Timer Period 1024 TOSC â 1024 TOSC â TOSC = OSC1 period
33
TPWRT Power-up Timer Period
â
65.5
75
ms
34
TIOZ I/O High-Impedance from MCLR
Low or Watchdog Timer Reset
â
2
â
μs
35
TBOR Brown-out Reset Pulse Width
200
â
â
μs VDD ⤠BVDD (see D005)
36
TIRVST Time for Internal Reference
Voltage to become Stable
â
20
50
μs
37
TLVD Low-Voltage Detect Pulse Width
200
â
â
μs VDD ⤠VLVD
38
TCSD CPU Start-up Time
5
â
10
μs
39
TIOBST Time for INTRC to Stabilize
â
1
â
ms
DS39760D-page 288
© 2008 Microchip Technology Inc.
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