AXIOMTEK MANO540 Series, User Manual

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MANO540 Mini ITX Motherboard
Watchdog Timer 55
Appendix A
Watchdog Timer
A.1 About Watchdog Timer
Software stability is major issue in most application. Some embedded systems are not
watched by human for 24 hours. It is usually too slow to wait for someone to reboot when
computer hangs. The systems need to be able to reset automatically when things go wrong.
The watchdog timer gives us solution.
The watchdog timer is a counter that triggers a system reset when it counts down to zero from
a preset value. The software starts counter with an initial value and must reset it periodically. If
the counter ever reaches zero which means the software has crashed, the system will reboot.
A.2 Sample Program
#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
#include <stdlib.h>
#ifdef _DEBUG
#define new DEBUG_NEW
#endif
#pragma comment ( lib , "User32.lib" )
#define IDT_TIMER WM_USER + 200
#define _CRT_SECURE_NO_WARNINGS 1
#define setbit (value,x) (value |=(1<<x))
#define clrbit (value,x) (value &=~(1<<x))
HINSTANCE hinstLibDLL = NULL ;
LONG WDTDATA = 0;
typedef ULONG (* LPFNDLLGETIOSPACE )( ULONG );
LPFNDLLGETIOSPACE lpFnDll_Get_IO;
typedef void (* LPFNDLLSETIOSPACE )( ULONG , ULONG );
LPFNDLLSETIOSPACE lpFnDll_Set_IO;
int _tmain ( int argc , _TCHAR * argv [])
{
int unit = 0;
int WDTtimer = 0;
if (hinstLibDLL == NULL )
{
hinstLibDLL = LoadLibrary ( TEXT ( "diodll.dll" ));
if (hinstLibDLL == NULL )
{
//MessageBox("Load diodll dll error", "", MB_OK);
}
}