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

[Emmanuel Fusté]

I don't know exactly for the 2B:
The "new" CPU is exactly the same SOC but with a new ARM core IP (quad 
core A7). All the peripherals IP are the same. Perhaps the USB core is 
different from the previous SOC, but I don't think so.
The external I/O chip (USB HUB and USBtoEthernet) is not the problem. 
The problem is the USB part of the SOC/Processor with is broken by design.

Emmanuel.

Le 03/03/2015 20:06, rgk a écrit :
>
> 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
>     <mailto: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
>     <mailto: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 <mailto:cyrus104 at gmail.com>
>     Date: Mon, 2 Mar 2015 08:00:50 -0500
>     To: hackrf-dev at greatscottgadgets.com
>     <mailto: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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