CyUSBEndPoint.XferData is returning false occassionally, but it's not because of a timeout.  My timeout value is 10 seconds.  When it fails, it fails quickly.

What other conditions would cause XferData to return false?

Receiving more data than what was requested can also cause this. Say we request 128 byte and the device responds with a 512 byte packet then it'll fail.

Most cases we run into this scenario when we work with short packets.

Anyways the error code should us more about the issue. Please let us know the error code being returned.

Regards,

Anand

Please get the error code using the LastError member varible of CyUSBDevice, it will give you the Win32 error code returned by GetLastErrorCode() Win 32 API.

Regards,

sai krishna.

It's returning a 997.  Overlapped I/O operation is in progress.

Is there a way to determine if the DMA producer is getting a overrun?

It is looking like IO is not completed yet,  application has to wait for more time. You might want to increase the time out for transfer, default time out is 10 seconds.

Regards,

sai krishna.

It's not a timeout.  It fails immediately.  I have seen timeouts and see the expected 10 second pause.  This is something else.

Hi dreitz

When you are calling the UsbdStatus() function does it also say that the state is STALLED witch status UNKNOWN? This is what is usually observe once the XferData function fails.

-Silvio

I get [state=HALTED status=UNKNOWN].

Hi, I meet the same error as yours, and I can not find any reason yet. 

dreitz and byeyear,

If you are using sync. SlaveFifo interface in your designs, you can try to decrease PCLK frequency to 90MHz or 95MHz.
We get same error message "[state=HALTED status=UNKNOWN]" when PCLK frequency is 100MHz. But 95MHz works fine.

Regards,
Ali

We are running PCLK at 50Mhz.  Would it matter that PCLK be divisible by 8 or something?  Kinda like the old baud rate frequencies...