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sending  a counter with USB Communication to PC

Question asked by jacob on Jul 26, 2011
Latest reply on Sep 14, 2011 by CraigG

Hi,

I am using the bf548 Eval board.

 

I am connected to the PC with USE Communitation, and i want to send a counter from the Eval Board

(usb_audio_app) to the PC and read it with MATLAB.

 

My Matlab script is very simple and reads the samples from the Eval Board (configured as an Audio Device).

 

I have a few questions:

  1. I think (though it is not clear) that the USB's phisical buffer is u32 (unsiged 32 bit Value). is it?  i want to send a fract32 value.
  2. i am sending a 200 u32 pack. the pack is a decreasing counter. I get a 42 - 43 sample pack. why is that?
  3. the samples that i send are very noisy. why is that.
  4. what is the sending rate?
  5. in this application, how can i see the SCLK? and the PLL divisors?

 

 

i have attached a figure of the samples as received by MATLAB. there you can see that the pack is 42 - 43 long and that is very noisy.

also attached is a text file with the samples received by the PC.

 

Thank you very much!

 

jacob

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