National Instruments TPC-2012 D

Windows CE includes a watchdog timer for the TPC-2012. You can access

the timer through the WIN32 API. The TPC-2012 includes a WDT driver,

WDT1:, for enabling/disabling the watchdog timer. You must open this

driver before using the resources, and then use the DeviceIOControl

function to enable/disable the watchdog timer.

This appendix describes DeviceIOControl and it parameters. It also

includes a programming example.

DeviceIOControl sends a control code directly to a specified device driver,

causing the corresponding device to perform the specified operation. The

function and its parameters are:

BOOL DeviceIoControl( HANDLE hDevice, DWORD

dwIoControlCode, LPVOID lpInBuffer, DWORD nInBufferSize,

LPVOID lpOutBuffer, DWORD nOutBufferSize, LPDWORD

lpBytesReturned, LPOVERLAPPED lpOverlapped );

DeviceIOControl includes the following parameters:

•hDevice

(in) Handle to the device that performs the operation. Call the

CreateFile function to obtain a device handle.

•dwIoControlCode

(in) Specifies the operation control code. This value identifies the

specific operation to be performed and the type of device on which the

operation is to be performed. No specific values are defined for the

dwIoControlCode parameter. However, if you write a custom device

driver, you can define IOCTL_XXXX control codes, per the CTL_CODE

macro. You then can advertise these control codes, and an application