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Pi vs BeagleBone-Black

Former Member

So, just over a year on from the initial availability of the R-Pi and the new BeagleBone Black is upon us.  They've obviously taken a leaf out of the RPF's playbook and produced a cost reduced version at a price only marginally above the Pi.

 

I find it interesting that the compromises are very different, for example there's a proper PMIC and the ethernet is not troubled by being connected to USB, however the on-board HDMI seems less capable.

 

Other differences are in the documentation, I'm currently viewing the pcb gerbers for the beaglebone..  Have yet to see any sign of those for the R-Pi a year later. There's even an up to date devicetree capable kernel too.

 

Technology has also moved on somewhat, we get a 1GHz Cortex A8 which is better than the Pi, along with various other stuff and lots more GPIO's too.

 

Ok, so it's clear that I like the look of the new beaglebone, and given the price I'm likely to put any further R-Pi plans on hold until I have a chance to play with this. It's also making things like the Olinuxino-maxi I bought recently look very slow/expensive while still being cheaper than the similarly specced Olinuxino-A13

 

Some details of the beaglebone-black here http://circuitco.com/support/index.php?title=BeagleBoneBlack

 

What do the rest of you think ?   I don't expect this to displace the Pi anytime soon, but I expect it to be very attractive to those people who don't simply want to put XBMC on it and duct tape it to the back of the TV..

Parents

  • selsinork wrote:

     

    jamodio wrote:

     

    Unfortunately there is and there will be no real fix for the usb issues with the Rpi.

    All sounds like an even better learning experience, a real world problem that can't be fixed. Lots of those exist, so learning how to deal with them and how to chose a compromise would be a useful skill ?

     

    What we have is not a fix but a work around, something very common from any semiconductor company where fixing some problems requires to go back to the silicon drawing board. The Synopsys USB IP included on the BCM2835 does not include a full host mode implementation so we (well them) are using a software layer to make it behave like a host, and since both the Synopsis stuff and Broadcom stuff are proprietary and under NDA getting other knowledgeable and capable people to contribute is almost impossible.

     

    The issue for the Rpi is that the USB interface is its primary way to communicate to the external world, ie other USB devices and Ethernet.

     

    And a major difference at this level between the Rpi and BBB is that the BCM2835 SoC has been developed as a multimedia applications processor, basically a video processor plus a ARM core for supervisory and general functions, on the other hand the Sitara AM355x is a generic microprocessor that is enhanced with image, and graphics processing, and other stuff.

     

    There are also some important differences between the ARM1176J core used on the BCM2835 and the Cortex-A8 used on the AM355x.

     

    This is a great introduction video from ARM about the ARM architecture fundamentals http://www.youtube.com/watch?v=7LqPJGnBPMM

     

    On about minute 8 you can see a slide similar to this one ...

     

    image

     

    Now, don't get confused (I always do) with the family version and the architecture version.

     

    ARM1176J is a v6 architecture, and Cortex-A8 a v7, where ARM introduced significant changes to support applications and the concept of hardware profiles and was designed from the scratch to support applications where a microcontroller has to run a full fledged operating system such as Linux.

     

    It is also important to note the different implementations of the same architecture, for example Cortex-A8 has a 13-stage pipeline when Cortex-A9 a 8-stage pipeline but both are v7A.

     

    So yes the primary differences between the Rpi and the BBB are under the hood and a big issue with the BCM2835 is that we are not even able to open the hood, we were just given the opportunity to sneak at the some of the GPIO stuff but not even electrical specs and functionality of those pins. For a school kid learning to program in phyton that won't make a big difference but for an embedded research and development engineer makes a big one.

     

    Unfortunately when somebody posted that his customers where not happy using the Rpi for embedded applications and I asked why, I've got a very flaky response.

     

    I'm still trying to explore the viability of the Rpi on this segment but with the actual proliferation of other alternatives (BBB included) the Rpi is loosing points every second.

     

    I'm about to test now the Wandboard with the quad Cortex-A9 Freescale i.MX6.

     

    Cheers

    Jorge

Reply

  • selsinork wrote:

     

    jamodio wrote:

     

    Unfortunately there is and there will be no real fix for the usb issues with the Rpi.

    All sounds like an even better learning experience, a real world problem that can't be fixed. Lots of those exist, so learning how to deal with them and how to chose a compromise would be a useful skill ?

     

    What we have is not a fix but a work around, something very common from any semiconductor company where fixing some problems requires to go back to the silicon drawing board. The Synopsys USB IP included on the BCM2835 does not include a full host mode implementation so we (well them) are using a software layer to make it behave like a host, and since both the Synopsis stuff and Broadcom stuff are proprietary and under NDA getting other knowledgeable and capable people to contribute is almost impossible.

     

    The issue for the Rpi is that the USB interface is its primary way to communicate to the external world, ie other USB devices and Ethernet.

     

    And a major difference at this level between the Rpi and BBB is that the BCM2835 SoC has been developed as a multimedia applications processor, basically a video processor plus a ARM core for supervisory and general functions, on the other hand the Sitara AM355x is a generic microprocessor that is enhanced with image, and graphics processing, and other stuff.

     

    There are also some important differences between the ARM1176J core used on the BCM2835 and the Cortex-A8 used on the AM355x.

     

    This is a great introduction video from ARM about the ARM architecture fundamentals http://www.youtube.com/watch?v=7LqPJGnBPMM

     

    On about minute 8 you can see a slide similar to this one ...

     

    image

     

    Now, don't get confused (I always do) with the family version and the architecture version.

     

    ARM1176J is a v6 architecture, and Cortex-A8 a v7, where ARM introduced significant changes to support applications and the concept of hardware profiles and was designed from the scratch to support applications where a microcontroller has to run a full fledged operating system such as Linux.

     

    It is also important to note the different implementations of the same architecture, for example Cortex-A8 has a 13-stage pipeline when Cortex-A9 a 8-stage pipeline but both are v7A.

     

    So yes the primary differences between the Rpi and the BBB are under the hood and a big issue with the BCM2835 is that we are not even able to open the hood, we were just given the opportunity to sneak at the some of the GPIO stuff but not even electrical specs and functionality of those pins. For a school kid learning to program in phyton that won't make a big difference but for an embedded research and development engineer makes a big one.

     

    Unfortunately when somebody posted that his customers where not happy using the Rpi for embedded applications and I asked why, I've got a very flaky response.

     

    I'm still trying to explore the viability of the Rpi on this segment but with the actual proliferation of other alternatives (BBB included) the Rpi is loosing points every second.

     

    I'm about to test now the Wandboard with the quad Cortex-A9 Freescale i.MX6.

     

    Cheers

    Jorge

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