C&T Solution CT-MCL01 Series, User Manual

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CT-MCL01 l User’s Manual
71
Watchdog Timer
Board Design
The Watchdog Timer (WDT) is implemented by Nuvoton NCT6106D.
Psuedo Code
#include<dos.h>
#include<stdio.h>
void main(void){
// for 2E
int x,pre_rd,rd,status;
clrscr();
outportb(0x2E,0x87);
outportb(0x2E,0x87);
outportb(0x2E,0x30); //CR30 bit1=1 pin77 select WDTO#
outportb(0x2F,0x01);
outportb(0x2E,0x07);
outportb(0x2F,0x08); //Logic Device8 (LD8)
outportb(0x2E,0x30);
outportb(0x2F,0x01); //Enable WDTO#
// Reset WDTO# and clear WDTO# timeout event
outportb(0x2E,0xF6);
outportb(0x2F,0x00); //Reset WDTO# Timer
outportb(0x2E,0xF7); //Logic Device 8, CRF7
outportb(0x2F,0x00); //Write Bit4=0 to clear WDTO# event!
// Input Timer value
printf("Enter WDTO# Timer(second):");
scanf("%d",&x);
pre_rd = x + 1;
// Set Timer and Start count
outportb(0x2E,0xF6); //LD8,CRF6h Set WDTO# Timer
outportb(0x2F,x);
// Check the timeout event
// LDN8 CRF7[4] = 1 (Timeout occur)
do{
// Read Count
outportb(0x2E,0xF6); //LD8,CRF6h Set WDTO# Timer
rd = inportb(0x2F);
// Read Timeout event
outportb(0x2E,0xF7); //Logic Device 8, CRF7
status = inportb(0x2F);
// check pre-status
if (rd < pre_rd){
printf("Timer = %d\n",rd);
pre_rd = rd;
}
}while(status != 0x10);
printf("Timer Timeout.\n");
printf("Input any key to reset timeout event\n");
getch();
// Reset WDTO# and clear WDTO# timeout event
outportb(0x2E,0xF6);
outportb(0x2F,0x00); //Reset WDTO# Timer
outportb(0x2E,0xF7); //Logic Device 8, CRF7
outportb(0x2F,0x00); //Write Bit4=0 to clear WDTO# event!
Appendix – WDT & GPIO