04-18-2013 11:03 AM
Hello! I am new to this discussion board.
I am currently designing a system capable of synthesizing an arbitrary waveform using a FPGA. The FPGA receives the samples from the PC via USB and then sends them to a DAC. Now I am interested in sending the samples recieved back to the PC using the USB Bulk Raw example provided with Labview software. So far I've managed to send from the PC to the FPGA over 350000 samples using this example but when I try to read them in the PC nearly half of the samples are lost, that is, if I send 350000 to the FPGA I can only receive 180000 approx. I've also noticed that if I do the same with 150 samples(bytes) it works fine but from that point doesn't. What's more, when sending the full amount of samples the first 150 received in the PC are correct, the following hundred is lost and then again correct. I thought that data are overwritten since they are read slower than they are sent by the FPGA. Could it be possible? If so I don't know if it is possible to change the size of the input buffer like a serial port.
Thank you all!
05-20-2013 05:45 PM
USB Bulk Raw example does not suit your pupose as you have to read the pipe with an event you generate manually by clicking the button. So make a simple application that continuosly read the pipe data at reasonably high rate may be every 10msec and collect all data into a buffer (array in SW) and later you can look at the data.
05-20-2013 06:16 PM