AnsweredAssumed Answered

STM32L151 Slow USB speed

Question asked by stokic.srdjan on Nov 27, 2014
Latest reply on Jan 28, 2015 by baroudi.badreddine
Hello all,

I have a quick question regarding the USB FS speed on STm32L151.

I managed to modify the sample code for USB VCP and get the USB running. I'm streaming my data to the PC succesfully.

The question is following. In order to start streaming I call the Handle_USBAsynchXfer() function and then whenever the EP1_IN_Callback() gets called, I copy 64 bytes into the PMA buffer, and set the EP1 valid. This way I'm streaming around 250KBit/s. This is painfully slow, and I would like to increase this speed somehow. Is there any way I can achieve greater speeds over USB?

Several places say that you can transfer more than 1 packet per frame interval (1msec), but I cannot figure out how to do this. Any help is appreciated.