AVR internal watchdog experiment-EEWORLD

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Experiment 12:

AVR internal door watch experiment.

1. Experiment of watching the door. Feed the dog periodically in the main program, and start the watchdog by pressing a button to make the program loop infinitely.

2. Internal 1 M crystal oscillator, the program adopts single-task mode and software delay.

3. To conduct this experiment, please plug in all 8 short-circuit blocks of JP1 and JP3, and the short-circuit block of JP7 (LED_EN).

4. Through this experiment, you can understand the settings of the watchdog and how to feed the watchdog.

#include "iom16v.h"

#include

/*Delay function*/

void delay_ms(unsigned char i) {

unsigned char a, b;

for (a = 1; a < i; a++) {

for (b = 1; b; b++) {

;

}

void main(void) {

DDRA = 0x00;/*Direction input*/

PORTA = 0xFF;/*Turn on pull-up*/

DDRB = 0xFF;/*Direction output*/

PORTB = 0xFF;/*Level setting*/

DDRC = 0x00;

PORTC = 0xFF;

DDRD = 0x00;

PORTD = 0xFF;

PORTB = 0x00;

WDR();/*Feed the dog*/

delay_ms(250);

WDR();/*Feed the dog*/

delay_ms(250);

PORTB = 0xFF;

WDTCR |= ((1 << WDTOE) | (1 << WDE));/*Startup timing*/

WDTCR = ((1<< WDE) | (1 << WDP2) | (1 << WDP1));/*Set the cycle to 1S*/

while (1) {

delay_ms(250);

WDR();/*Feed the dog*/

PORTB ^= (1 << 0);/*PB0 level inversion*/

while(PINA != 0xFF);/*Detect key press*/

}

Keywords：AVR Reference address：AVR internal watchdog experiment

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