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EZ-USB FX3 APIs Length Limit | Cypress Semiconductor

EZ-USB FX3 APIs Length Limit

Summary: 1 Reply, Latest post by PRAG on 10 Sep 2014 02:13 PM PDT
Verified Answers: 0
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user_354537326's picture
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I am using EZ-USB FX3 DVK and also 1.3 SDK installed. I am using the asynchronous APIs given by Streamer Source code to replicate the same in custom Visual C++ Application. In the application I am calling the BeginDataXfer() API with a length field value of 1024bytes. But after FinishDataXfer() I am actually getting data with a length of 16384bytes. i.e., what ever value(multiples of 1024) i have given inbetween any 16384 multiples I am getting output data with a length of 16384bytes.

In other words, if any number which is not a multiples of 16384bytes is given as length to BeginDataXfer(), WaitforDataXfer() and FinishDataXfer(), the final outuput buffer is always havin an length of 16384bytes.

How to resolve this issue ? Is it the limitation of Asynchronous API ?



Gokul Prasath N

PRAG's picture
Cypress Employee
173 posts



How many async queues are you setting up in your application?

Are you using the OVERLAPPED structure in these calls and making sure to execute the Wait() and Finish() calls accordingly (in the correct order of queuing)?


And what type of endpoint are you reading the data from? Is it bulk or isoc?


Did you parse the received buffer of 16384 bytes to see if all the data is actually correct? Do you by any chance see any junk data in the received buffer?





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