PIC18F2450/4450
In addition to their Power-up and Oscillator Start-up
Timers provided for Resets, PIC18F2450/4450 devices
have a Watchdog Timer, which is either permanently
enabled via the Configuration bits or software controlled
(if configured as disabled).
18.0 SPECIAL FEATURES OF THE
CPU
PIC18F2450/4450 devices include several features
intended to maximize reliability and minimize cost
through elimination of external components. These are:
The inclusion of an internal RC oscillator also provides
the additional benefits of a Fail-Safe Clock Monitor
(FSCM) and Two-Speed Start-up. FSCM provides for
background monitoring of the peripheral clock and
automatic switchover in the event of its failure. Two-
Speed Start-up enables code to be executed almost
immediately on start-up, while the primary clock source
completes its start-up delays.
• Oscillator Selection
• Resets:
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
All of these features are enabled and configured by
setting the appropriate Configuration register bits.
• Watchdog Timer (WDT)
• Fail-Safe Clock Monitor
• Two-Speed Start-up
• Code Protection
• ID Locations
• In-Circuit Serial Programming
The oscillator can be configured for the application
depending on frequency, power, accuracy and cost. All
of the options are discussed in detail in Section 2.0
“Oscillator Configurations”.
A complete discussion of device Resets and interrupts
is available in previous sections of this data sheet.
© 2006 Microchip Technology Inc.
Advance Information
DS39760A-page 189
MICROCHIP [ MICROCHIP ]
