Personal Computer User Manual

Appendix D Watchdog Timer Programming on WinCE

IOCTL_WDT_REBOOT

If you want your application to trigger the watchdog, use

IOCTL_WDT_REBOOT to notify the watchdog driver timer (WDT).

Otherwise, the WDT triggers itself automatically.

•

lpInBuffer: unused

•

nInBufferSize: unused

•

lpOutBuffer: unused

•

nOutBufferSize: unused

Programming Example

#define WDT_CODE(ID) CTL_CODE(FILE_DEVICE_UNKNOWN,ID, METHOD_BUFFERED,

FILE_ANY_ACCESS)

#define IOCTL_WDT_ENABLE WDT_CODE (0x900)

#define IOCTL_WDT_DISABLE WDT_CODE(0x901)

#define IOCTL_WDT_STROBE WDT_CODE(0x902)

#define IOCTL_WDT_GET_TIMEOUT WDT_CODE(0x903)

#define IOCTL_WDT_SET_TIMEOUT WDT_CODE(0x904)

#define IOCTL_WDT_REBOOT WDT_CODE(0x905)

// for compatibility reasons, you can define IOCTL as below:

// #define IOCTL_WDT_ENABLE 0x1001

// #define IOCTL_WDT_DISABLE 0x1002

// #define IOCTL_WDT_STROBE 0x1003

// #define IOCTL_WDT_GETTIMEOUT 0x1004

// #define IOCTL_WDT_SETTIMEOUT 0x1005

// #define IOCTL_WDT_REBOOT 0x1006

HANDLE m_hWDT=NULL;

TCHAR szClassName[60];

// assign the WDT driver name wsprintf(szClassName, TEXT("WDT1:"));

// Open the WDT driver

m_hWDT = CreateFile(szClassName, GENERIC_READ GENERIC_WRITE, 0, NULL,

OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

if ( m_hWDT == INVALID_HANDLE_VALUE ) { DebugMsg(CString("WDT driver fail"));

return;

}

DWORD dwTemp; DWORD nIndex=2;

// Set the Watchdog Timer as 10 seconds. Number 2 means 10 seconds.

DeviceIoControl(m_hWDT, IOCTL_WDT_SET_TIMEOUT, &nIndex, sizeof(nIndex),

NULL, 0, &dwTemp, NULL);

// Enable the Watchdog timer

DeviceIoControl(m_hWDT, IOCTL_WDT_ENABLE, NULL, 0, NULL, 0, &dwTemp, NULL);