watchdog timer

[Anderson_87]

Hi,
I would like to know about the watchdog Timer.
I am working on CCS compiler and i want to know at what time the reset occurs. My code is


#include <16F877A.h>
#fuses WDT,XT

int8 i,j;

void main()
{
TRISA=0x00;
TRISB=0x00;
TRISC=0x00;
TRISD=0x00;
TRISE=0x00;

PORTA=0x00;
PORTB=0x00;
PORTC=0x00;
PORTD=0x00;
PORTE=0x00;

OPTION_REG=0X88;
INTCON=0XE0;
T0IE=1;

switch(restart_cause())
{
case WDT_TIMEOUT:
lcd_putc("\fwatch timeout");
break;
case NORMAL_POWER_UP:
lcd_putc("\fnormal time out");
break;
}

setup_wdt(WDT_2304MS);

while(true)
{
lcd_putc("\fnormal operation");
while(1);

}

}

 

[alec_t]

From the datasheet the WDT period is from 7 to 33 mS (typically 18 mS) with no prescaler, but it looks as though your code assumes 18 mS and sets the prescaler to 128 to give a period of 2304 mS. In reality the period could be anywhere from 896 to 4224 mS.

 

[WTP Pepper]

main is not terminated with a } for a start.