Maxium data rate across Virtual Com Port

[gareth2]

Posted on October 25, 2011 at 20:54

Hi all,

I am am currently working on a system whereby we would like to stream event generated data at rates of 100Mbit/s+ across the usb to a debug terminal on the host. We are using the STM32F207 device and its HS USB port. Starting with the example virtaul com port code provided by ST I was able to remove the UART and then access the circular buffer APP_RX_DATA to implement my code. However the data rates I seem to be getting are: 1. varied (im guessing an OS issue on the PC. 2. Reasonably slow 11-14Mbits/s Am I trying to do something that is not possible here? If so is there a better way of doing this? Thanks for your help in advance. #stm32f207-cdc-virtualcom-usb

[emalund]

Posted on October 26, 2011 at 14:56

to do this I'd set everything at max and code ''ready tests'' wherever applicable.

nothing goes ready before it is done and thus max speed with wait for ready will give you the highest throughput you can possible achieve.

[gareth2]

Posted on October 26, 2011 at 16:27 Hi, Thankyou for the reply, do you have any feel for what would be an expected maximum speed? Cheers, Gareth

[emalund]

Posted on October 26, 2011 at 17:08 nope 1) you do not state your sysclk speed 2) still using 1xxx Erik

[Tesla DeLorean]

Posted on October 26, 2011 at 17:36

Am I trying to do something that is not possible here? If so is there a better way of doing this?

Somehow I think a Mass-Storage Device (bulk), or a streaming video source (isochronous), would seem to be a better model.

[gareth2]

Posted on October 26, 2011 at 23:43

Hi Clive1,

Thank-you for the reply. You are correct, streaming using the audio class would be a more suited option but (i believe) this would require work at the windows driver end which is not an option in my case. What are your thoughs on the Virtual com method? should it be possible (if not ideal) and have you seen this done before? Cheers, Gareth