Hi !
I'm using NI DAQ mx Driver with a pci-6509 board.
I'm able to read or write on port lines ( using change detection ), but when i do this, I use 100% of my CPU ressources !!!
This is my C++ code :
	DAQmxCreateTask("",&taskHandle);
	DAQmxCreateDIChan(taskHandle,"Dev1/port0/line0","",DAQmx_Val_ChanForAllLines);
	DAQmxCfgChangeDetectionTiming(taskHandle,"Dev1/port0/line0","Dev1/port0/line0",DAQmx_Val_FiniteSamps,1);
	DAQmxStartTask(taskHandle);
	for (;;)
	{	
		data[0] = 0;
		DAQmxWaitUntilTaskDone (taskHandle, -1);
		ii = DAQmxReadDigitalLines (taskHandle,1,DAQmx_Val_WaitInfinitely,DAQmx_Val_GroupByChannel,data,sizeof(data),&numRead,&bytesPerSamp,NULL);
		etat = data[0];
		DAQmxStopTask(taskHandle);
	
}
	DAQmxStopTask(taskHandle);
	DAQmxClearTask(taskHandle);
Is this the correct way for perform change detection, and why I use 100% of CPU time when I read line state ??
Any help would greatly be appreciated.
Thank you for your reply !
Val