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USB packet not sent if size equal to buffer size

Question asked by Frederic Parent on Nov 5, 2013
Latest reply on Dec 17, 2013 by Frederic Parent

Hi all,

 

I'm using KM20DN512 in USB slave device connected to a windows PC with winUSB driver.

 

I use the original MQX 4.0 usb device driver with endpoint buffer size to 64bytes in BULK. In according to CDC example demo, I send a zero lenght packet if the modulo of data size to send is equal to endpoint buffer size (data size % 64 == 0). But my problem is if the data size to send is exactly equal to endpoint buffer size, the data packet is not sent (I see no data transaction with the USB sniffer ie TotalPhase Beagle) and I only see the zero lenght packet. In other words, the data packet is sent if size >64 or size<64, not sent if size==64. I have already read and post on this thread with no satisfying answer: https://community.freescale.com/message/304117#304117

 

Someone have any idea to finally solve this issue?

 

Thanks!

 

Frédéric Parent

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