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Calling DCD_EP_Tx() multiple times

Question asked by senanayake.pradeepa on Sep 3, 2013
Latest reply on Sep 6, 2013 by senanayake.pradeepa

I've been experimenting on USB devices on STM32F4 discovery board. I have a small issue.

From the PC I send multiple messages (bulk_writes) to the USB, and I call 'dcd_ep_tx' within the Data_out function which invokes upon transfer complete interrupt on OUT packets. 

The issue is when I do this and later when I read the same endpoint, I can receive around 4~7 packets which I have previously sent to the device. I still could not find the source for this behavior. I'm using the cdc example as the foundation in this application.

Is this due to some sort of a FIFO? If so where is it implemented?

My TX1 FIFO size is 128.

I hope the question is clear. 

Thank you in advance.