[Hackrf-dev] <DKIM> Re: HackRF with Raspberry Pi 2 Overruns

[rgk]

Is this a problem with the RP B/B+ or the RP 2B or all of the above? All the RP's have the same IO chip, but the Pi 2B has a totally different CPU and that new chip on the bottom of the board. If I sound non-specific it's because I just got a Pi 2B and have had little time to research its new features and capabilities. I think if the IO chip is the problem (just not enough throughput) then what can be done to minimize the over run issues?

 
Date: Tue, 3 Mar 2015 08:45:01 +0100
From: emmanuel.fuste at laposte.net
To: hackrf-dev at greatscottgadgets.com
Subject: Re: [Hackrf-dev] <DKIM> Re:  HackRF with Raspberry Pi 2 Overruns


  
    
  
  
    It is a congenital deficiency of the
      RPi. It needs near realtime response and an awfull amount of CPU
      to not drop usb transactions.

      Search Rpi usb split transaction on google.

      

      Emmanuel.

      Le 03/03/2015 04:36, Silverfox a écrit :

    
    
      
      
      
      
      
        I
            don't think it is unreasonable for the PI to cause overruns
            but others may prove me wrong.  It takes considerable
            horsepower to process the data without overruns.  However,
            if you aren't doing heavy processing in the flowchart.  FFT
            is probably the biggest consumer of cycles.
        73,
        Alan
            - W6ARH
         
        
          From:
              HackRF-dev
              [mailto:hackrf-dev-bounces at greatscottgadgets.com] On
                Behalf Of Derek Murphy

              Sent: Monday, March 2, 2015 6:41 PM

              Cc: hackrf-dev at greatscottgadgets.com

              Subject: Re: [Hackrf-dev] HackRF with Raspberry Pi
              2 Overruns
        
         
        
          Donald, I changed the sample to 2e6 and
            then up to 4e6, both way the Overrun indicator starts to
            appear faster and then fills the terminal window faster.
          
             
          
          
            I am not sure if I have something wrong
              with the driver or kernel config. It's a stock kernel from
              the raspbian distro. I tried a couple of different USB
              ports on the pi with no change.
          
        
        
           
          
            On Mon, Mar 2, 2015 at 2:22 PM, rgk
              <rgkenders at hotmail.com>
              wrote:
            
              
                

                  I am currently building a completely portable pi 2
                  setup that runs off of LIPOs. This is my intended
                  purpose...IE my hackRF on my pi. I'm very interested
                  in what others have done similar to this.
                
                  
                    
                  From: cyrus104 at gmail.com

                    Date: Mon, 2 Mar 2015 08:00:50 -0500

                    To: hackrf-dev at greatscottgadgets.com

                    Subject: [Hackrf-dev] HackRF with Raspberry Pi 2
                    Overruns
                  
                    
                       
                      
                        I wanted to see if anyone
                          has had similar experience with the Raspberry
                          Pi / Pi 2 with regards to the HackRF.
                        
                           
                        
                        
                          The USB port bandwidth
                            was was around 18MB when I ran the transfer
                            test.
                        
                        
                           
                        
                        
                          When I get into GNU, I
                            have a very simple example that show the
                            standard fft on coming from the hackrf
                            source. I have the sample rate set to 1.0e6
                            but also run into similar issues when I run
                            at 64k. I get the OOOOOO being posted and
                            not just when I start the application.
                        
                        
                           
                        
                        
                          Thanks
                        
                      
                       
                    
                  
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