Hi Haitao,
The easiest and best way to get started with handshaking burst protocol is to take a look at the shipping examples with NI-DAQ. When you installed support for NI-DAQ, you should have had the option to install support for VB, VC++ etc. selecting these will install the example programs in the NI-DAQ/samples directory. Sometimes it is useful to also install the VC++ or CVI ones because the examples can give you a reference to how to program.
That being said, I think that there is probably a parameter or a call that is not quite configured correctly in your code. Another thing to take into account is the device you are communicating with. It could be that the device can only handle 15 samples and when the PCI-6534 uses burst mode at upto 20MHz, i
t could be transferring data to quickly. What is probably occuring in that case is that the card is sending the data but the receiving device is not acknowledging all the data. For instance, if you are passing a buffer of data with 100 samples, they will all be stored on the 6534's FIFO and the only thing preventing it from outputting correctly once configured to do so is the handshaking control lines for burst mode.
Anyway, I would start with those suggestions to see if we can isolate the problem and then work from their. Let me know if you have any other questions that might help. Have a good day.
Ron
