Unable to transmit 1Mbytes in 1 second through STM3240G-EVAL USB Hi-Speed Port

jagdish · ‎2013-12-06

Posted on December 06, 2013 at 13:13

Hi,

I am trying USB hi-speed virtual com port example on STM3240G-EVAL board. I am using the USB device library from ST. Primary stage of data exchange between development board and PC over USB Hi speed port is achieved. Further as per my application's need, what I am trying to achieve is

''transmitting 1 Mbytes in 1 second from dev board to PC''

. But unable to achieve this. When I am capturing the data I observe that it takes approximately 8 seconds to transmit 1Mbytes.

Kindly guide me to resolve this issue. Also do let me know if any you more details are needed.

thanks,

Jagdish

#usb-virtual-com-port #stm3240g-eval #stm3240g-eval #usb-virtual-com-port

Andrew Neil · ‎2013-12-06

Posted on December 06, 2013 at 16:17

''I observe that it takes approximately 8 seconds to transmit 1Mbytes''

How, exactly, do you measure that?

Tesla DeLorean · ‎2013-12-06

Posted on December 06, 2013 at 16:54

You'd want to make sure to send large packets of data. You don't have source to the driver, so it might be hard to determine the limits there.

Evaluate for example the MSC class and see the speed there. Then you'll have some numbers to compare, and work with in the VCP implementation.

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dthedens23 · ‎2013-12-06

Posted on December 06, 2013 at 20:17

try using Linux as the host.

might just be a Windows driver limitation.

jagdish · ‎2013-12-08

Posted on December 09, 2013 at 05:12

Hi,

I tried sending blocks of 512 bytes for one second and captured it in file using HERCULES serial port application. I found that in a second the file that was created was of around 300 kBytes size. I tries adjusting the FRAME interval setting available in the ''usbd_conf.h'', but no change in the end affect.

Jagdish