Книга: Advanced PIC Microcontroller Projects in C
2.1.7 Watchdog Timer
2.1.7 Watchdog Timer
In PIC18F-series microcontrollers family members the watchdog timer (WDT) is a free-running on-chip RC-based oscillator and does not require any external components. When the WDT times out, a device RESET is generated. If the device is in SLEEP mode, the WDT time-out will wake it up and continue with normal operation.
The watchdog is enabled/disabled by bit SWDTEN of register WDTCON. Setting SWDTEN = 1 enables the WDT, and clearing this bit turns off the WDT. On the PIC18F452 microcontroller an 8-bit postscaler is used to multiply the basic time-out period from 1 to 128 in powers of 2. This postscaler is controlled from configuration register CONFIG2H. The typical basic WDT time-out period is 18ms for a postscaler value of 1.
Оглавление книги
- 2.1.1 Program Memory Organization
- 2.1.2 Data Memory Organization
- 2.1.3 The Configuration Registers
- 2.1.4 The Power Supply
- 2.1.5 The Reset
- 2.1.6 The Clock Sources
- 2.1.7 Watchdog Timer
- 2.1.8 Parallel I/O Ports
- 2.1.9 Timers
- 2.1.10 Capture/Compare/PWM Modules (CCP)
- 2.1.11 Analog-to-Digital Converter (A/D) Module
- 2.1.12 Interrupts
- 1.3.3 Timers
- 1.3.4 Watchdog
- 11.7 Soft Timers and Timer Related Operations
- 2.1.9 Timers
- PROJECT 6.7 — Two-Digit Multiplexed 7-Segment LED Counter with Timer Interrupt
- Chapter 11: Timer and Timer Services
- 11.3 Programmable Interval Timers
- 11.4 Timer Interrupt Service Routines
- 11.5 A Model for Implementing the Soft-Timer Handling Facility
- 14.3.3. Интервальные таймеры: setitimer() и getitimer()
- Модуль Timers
- 8.13. Функция setitimer(): задание интервальных таймеров