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Appendix
Appendix A: Watchdog Timer (WDT) Setting
WDT is widely used for industry application to monitor the activity of CPU. Ap-
plication software depends on its requirement to trigger WDT with adequate
timer setting. Before WDT time out, the functional normal system will reload
the WDT. The WDT never time out for a normal system. The WDT will not be
reloaded by an abnormal system, then WDT will time out and reset the system
automatically to avoid abnormal operation.
This board supports 255 levels watchdog timer by software programming I/O
ports. Below are the source codes written in C, please take them as WDT ap-
plication example.
/*---------------------------------------------------------------------------*/
#include <math.h>
#include <stdio.h>
#include <dos.h>
int WDTCount;
int main(void)
{
unsigned char
iCount;
printf(“WDT Times ( 1 ~ 255 ) : “);
scanf(“%d”,&iCount);
printf(“\n”);
WDT_Start(iCount);
return 0;
}
void WDT_Start(int iCount)
{
outportb(0x66,0xBA);
/* Enable Watch Dog */
delay(2000);
WDTCount = iCount;
outportb(0x62, WDTCount);
/* Number is Watch Dog Down count number */
delay(2000);
outportb(0x62, 0x00);
/* Minute is 1 count unit by minute */
/* Minute is 0 count unit by second */
}
Summary of Contents for EmETXe-i88U4-D1508
Page 1: ...EmETXe i88U4 COM Express Compact Type 6 CPU Module User s Manual Version 1 0 2020 07...
Page 2: ...Revision History Version Date Description 1 0 2020 07 Initial release...
Page 9: ...1 Introduction 1 Chapter 1 Introduction...
Page 14: ...6 This page is intentionally left blank...
Page 15: ...7 Board Overview 2 Chapter 2 Board Overview...
Page 17: ...9 Board Overview 2 2 Board Dimensions...
Page 22: ...14 This page is intentionally left blank...
Page 23: ...15 Installation Maintenance 3 Chapter 3 Installation Maintenance...
Page 26: ...18 This page is intentionally left blank...
Page 27: ...19 BIOS 4 Chapter 4 BIOS...
Page 57: ...49 Appendix Appendix...
