How do you use the freqout as the sample clock for writing data to DO of 6224 PCI

[VJohnson]

Using PCI-6224, I am currently trying to output data using the freqout as a sample clock reference for a Digital Output channel. I hook up the scope to see the clock on the freqout pin. However, the data seems to be missing. How can I output the data correctly using the reference for timing? What am I missing that links the two signals together? Any help would be greatly appreciated. I am writing this code in MS VS C++ and here is what I have done so far:

        int32       error=0;
        TaskHandle  taskHandle=0;
        TaskHandle  taskHandleFRQ=0;
        char        errBuff[2048]={'\0'};
	uInt8       data[8]={1,0,1,1,1,0,1,0};
	
	/*********************************************/
	// DAQmx Configure Clock
	/*********************************************/
	DAQmxErrChk (DAQmxCreateTask("",&taskHandleFRQ));
	DAQmxErrChk (DAQmxCreateCOPulseChanFreq(taskHandleFRQ,"Dev2/freqout","",DAQmx_Val_Hz/*Units*/,DAQmx_Val_Low/*IdleState*/,0/*Delay*/,10000/*Freq*/,0.5/*DutyCycle*/));
	DAQmxErrChk (DAQmxCfgImplicitTiming(taskHandleFRQ,DAQmx_Val_ContSamps,8));

	/*********************************************/
	// DAQmx Configure Digital Output
	/*********************************************/
	DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
	DAQmxErrChk (DAQmxCreateDOChan(taskHandle,"Dev2/port0/line0","",DAQmx_Val_ChanPerLine));
	DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"/Dev2/PFI14",10000,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,8));
		
	/*********************************************/
	// DAQmx Write Code
	/*********************************************/
	DAQmxErrChk (DAQmxWriteDigitalLines(taskHandle,8,0,10.0,DAQmx_Val_GroupByChannel,data,NULL,NULL));

	/*********************************************/
	// DAQmx Start Code
	/*********************************************/
	DAQmxErrChk (DAQmxStartTask(taskHandleFRQ));
	DAQmxErrChk (DAQmxStartTask(taskHandle));

[aNIta B]

Hi!

      I believe that you're setting up your clock wrong, I would recommend following the instructions in this Knowledge Base article that explain how to use and program the FREQ OUT line.  Have a good one!

[VJohnson]

The reference is to a LabVIEW example. Is there an example done in C/C++ that would be helpful?

[VJohnson · Accepted solution]

I believe that the original code was operational. However, since the transmission of the data was set to finite, I was having a hard time viewing the data on my scope. By changing the value from DAQmx_Val_FiniteSamps to DAQmx_Val_ContSamps, I was able to easily see the data.

My mistake. I am still learning here. Thanks for the time.