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Issues facing with Cypress USB3.0 Driver for Bulk Data Receive from device | Cypress Semiconductor

Issues facing with Cypress USB3.0 Driver for Bulk Data Receive from device

Summary: 2 Replies, Latest post by Andrew.James_1539786 on 09 Dec 2015 12:54 AM PST
Verified Answers: 0
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RajHegde's picture
2 posts

 Dear Cypress Support,

We are using following synchronous bulk transfer API for receiving bulk data from the Cypress USB 3.0 Complaint device

TimeOut = 2000; //set as 2 sec
CyBulkEndPoint bulkEpt = curEndpt as CyBulkEndPoint;             if (bulkEpt != null)             {                 bXferCompleted = bulkEpt.XferData(ref buffer, ref bytes, true);                 CheckForScripting(ref buffer, ref bytes);             }

However, with this API we are able to receive data for sometime correctly. After few min, the data received from the XferData API will be corrupted with the following values

bytes/data length as 64 bytes

buffer data for length of 64 as 00

bXferCompleted as true
If we read the value of device state and status for the last call using UsbdStatusString(), then this API is returing
Status = SUCCESS

Can you please help in debugging this issue ? Is this a bug with synchronous API ? We have changed timeout value by increasing and decreasing to different values, but that was of no use.

RajHegde's picture
2 posts

 Can anyone help me with some resolution.


Rajesh Hegde

Andrew.James_1539786's picture
1 post

We are seeing a similar problem with an FX2 using CyUSBEndPoint.

The XferData works for a time (usually around a minute) and then we receive a buffer of the correct length (512 bytes), but filled with zeros. If we read again, the buffer is populated with data from the next packet, indicating that when the failure occurs, a packet has been read from the USB, but that we have received zeros. Using a USB analyzer, the lost packet is definitely transmitted across USB.

As above, we get no notification of anything being wrong from the status information.

Windows 7, CyUSB3.sys version, CyUSB.dll version, C# client in Visual Studio 2013

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