archee
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Re: ARMv7 (Cortex-A8)

Fri Jan 13, 2012 11:10 pm

The ARMv7  (Cortex-A8) with 1GHz appears in a lot of Android phones together with a good GPU.

I don't know how much is the difference in cost to the ARMv6 (ARM11) which you are using, but probably marginal.You might even make a deal for co-production with a phone maker to save cost (I'm not a hardware guy, so IDK)

I think choosing already outdated chips is generally a bad idea for the future, just like PlayStation 3 failed with the weak GPU.

It's also a good lesson to children to understand the concept of SIMD on the ARMv7 with NEON.

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Re: ARMv7 (Cortex-A8)

Fri Jan 13, 2012 11:49 pm

Probably marginal?  Think again.  There's a reason that things like the BeagleBoard and BeagleBone are priced the way they are ($100-ish for the BeagleBone, $150-ish for the BeagleBoard...with a similar deal to the R-Pi Foundation's from Broadcom to the BeagleBoard people from TI...).  Part of it is the overall cost of an A8 core on the things.

They will get to making a new spin of the R-Pi (Mk II??) when it becomes practical to do so and they can make it where it's priced down around the same price point the current generation is.

The only big, big things about an A8 over this is that it's 3-4 times faster at clock because of the in-order superscalar nature and NEON, which is nice, but has issues in the A8 and using VFP code (You get pipeline stalls using NEON and then immediately trying for the regular FP accelerator on an A8.  Bad stalls.).  It's nice to have all of this, but they'd just be making yet another BeagleBoard, Pandora Handheld, etc. at that point- and it'd be priced the same.

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Re: ARMv7 (Cortex-A8)

Sat Jan 14, 2012 12:32 am

You have to remember who the raspberry Pi team are catering for here. They are aiming for the schools first and then the hobbyists. Cost was a big factor as nobody could ever envision a school child being allowed to spend £100 on a piece of PCB with a Cortex8 attached to it. Now £11, that is a weeks pocket money.

It may also surprise you that there have been (and still are) many Android devices built on the ARM11 core. You might be even more surprised to hear that over the last year many Android device manufacturers have been moving away form the Cortex-A8 as that is rapidly becoming outdated (sad I know, it has served me well).

However if a Cortex A8 device is what you would like to see, then as you could look into the Beagle/Panda boards as Svaltalf mentioned. You may also want to look at the pandora, that is a very nice piece of kit.

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Re: ARMv7 (Cortex-A8)

Sat Jan 14, 2012 12:51 am

Thanks, I didn't know, the A8 was so expensive.

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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 7:37 am

BeagleBone site says:

The BeagleBone uses a TI AM3358 ARM Cortex-A8-based microprocessor. Announced on Oct 31, 2011, the main processor is available for as little as $5, uses a 0.8mm ball-grid array and standard DDR2 memory, making this board easier to clone than other BeagleBoard designs.

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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 9:46 am

Be interesting to know at what quantities you get that $5 price. Lots and lots would be my guess because that is very cheap for a A8.
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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 10:13 am

offtopic...Did the PS3 fail?

Like lots of the posts asking for more cpu power/more ram/more anything...it comes down to the massive balancing act the foundation has had to do.

You take the costs of each component, then look at what impact each has, which ones need extra components, what impact to routing on the board, what is integrated, what isn't, what support there is to get the best out of it...jumble it up to work out a cost and then do it again and again until you get even slightly close to what you aim for.

It is probably safe to say that the broadcom assistance probably has been key, and the unit price of the cpu is only a small aspect of this.

It'll be interesting to see what we can achieve with the RPi...even if it is low spec (the ARM core...the GPU is something else), we've already seen some real treats, can't wait to see how far it'll go.
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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 12:32 pm

archee said:


I think choosing already outdated chips is generally a bad idea for the future, just like PlayStation 3 failed with the weak GPU.

It's also a good lesson to children to understand the concept of SIMD on the ARMv7 with NEON.


It is a much better idea for children to learn on a limited system and then scale up to bigger and better machines, than to learn on a system with vast resources and then find that they can't get things to work on smaller systems.

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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 2:28 pm

bbramble said:


archee said:


I think choosing already outdated chips is generally a bad idea for the future, just like PlayStation 3 failed with the weak GPU.

It's also a good lesson to children to understand the concept of SIMD on the ARMv7 with NEON.


It is a much better idea for children to learn on a limited system and then scale up to bigger and better machines, than to learn on a system with vast resources and then find that they can't get things to work on smaller systems.


One could argue that using current generation chips is also a bad idea for the future, for the same reasons!

I agree that limited systems promote decent coding - after all, systems are only going to get bigger, so even today's 'big' systems will be limited systems tomorrow. So good coding now is future proof.
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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 5:45 pm

Sure, they could do the same with an Atom Z processor and create a Windows based Pi, but I estimate a system like that would still cost over $80 at this point in time (ship+tax incl).

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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 6:50 pm

All of the Beagle products have way too much profit included in the price.  TI funds that project so someone has to be pocketing some cash.  I'm hoping that when the R-Pi gets released it will drive their prices down to more realistic levels.

The Beaglebone should be in the $50 range and the two Beagleboards need to get some price drops as well.  While more capable than the R-Pi their prices are way out of line.  As more ARM based computers get released the market will become more competitve and hopefully that will result in more capable lower priced boards.

With schools and learning tools like this it will be all about cost.  I would venture to say that more R-Pis would sell at $15 than at $25.  That means that getting cost down will be a great value (as opposed to increasing performance at the same price) to acheaving the foundation's goals of making an educational product.  Would I pay for more capablility?  Yes, but I'm not going to hound them to make a tailored product for my needs.  If the R-Pi fits my project's needs then I will buy one if not then I buy something else.  If nothing exists at a price I'm willing to pay then I wait.

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Re: ARMv7 (Cortex-A8)

Thu Mar 29, 2012 8:52 pm

archee said:.


I don"t know how much is the difference in cost to the ARMv6 (ARM11) which you are using, but probably marginal.


It not "marginal", its not even "expensive", its simply impossibly!

The CPU isn"t a separate chip, its simply part of the SoC (system on a chip) that the RPF have chosen to base the R-pi on. This was an existing chip developed by Broadcom for the mobile device market, its actually more a GPU that has a CPU attached to it as an "afterthought" than it is a CPU which happens to be integrated with a great GPU, but that aside.

The real point is that this is an existing chip, which happens to have an internal ARM11 CPU inside, the CPU alone cannot be exchanged with another one without a complete redesign of the SoC, and this won"t happen unless there is demand from the mobile market for such a chip, which at this point in time isn"t really likely and would also result in a necessary redesign of the R-pi, and a fractioning of the user base in "older R-pi" and "new R-pi" users which is contrary to the goals of the RPF.

But wait a bit and "clones" of the R-pi are bound to happen, not adhering to the goals of the RPF, and obviously these are going to compete on technical grounds, so one with a faster CPU is bound to arrive sooner or later. The "ghost is out the bottle", now that producers are realizing that you can indeed build a "desktop PC" for much less than when using the older paradigm of using conventional PC hardware.

Hopefully the R-pi will remain as is and will not be changed because of this, and will keep a large and enthusiastic following.

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Re: ARMv7 (Cortex-A8)

Fri Mar 30, 2012 5:00 am

archee said:

I think choosing already outdated chips is generally a bad idea for the future, just like PlayStation 3 failed with the weak GPU.
It takes quite a few years for a chip to be outdated. New products are still sold and even developed with an ARMv6 chip. I've just received a new smartphone with such as chip.

ARMv6 also have SIMD instructions, although it's not NEON. I would also consider playing with SIMD instructions (matrix / vector operations) to be quite a specialist task and children would have to have passed the corresponding Maths class first.

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Re: ARMv7 (Cortex-A8)

Fri Mar 30, 2012 8:48 am

cnxsoft said:


archee said:


I think choosing already outdated chips is generally a bad idea for the future, just like PlayStation 3 failed with the weak GPU.


It takes quite a few years for a chip to be outdated. New products are still sold and even developed with an ARMv6 chip. I've just received a new smartphone with such as chip.

ARMv6 also have SIMD instructions, although it's not NEON. I would also consider playing with SIMD instructions (matrix / vector operations) to be quite a specialist task and children would have to have passed the corresponding Maths class first.


I mentioned this elsewhere, but the Armv6 + GPU combo in the Raspi's SOC is quite a powerful combination for a lot of embedded devices that simply don't need any more power. The Roku is a case in point, and there are more examples of use cases where the v6 is perfectly capable.

That said, you can always make use of more CPU power, as can be seen by increasing horsepower in many mobile devices.
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Re: ARMv7 (Cortex-A8)

Fri Mar 30, 2012 5:45 pm

I would think that down the road when RasPi has, hopefully brought more students into programming, it may be time to build a more powerful board. It would be nice if there was a cheaper set of developer boards available for advanced students to take the next step.
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Re: ARMv7 (Cortex-A8)

Sat Oct 04, 2014 10:27 pm

jamesh wrote:Be interesting to know at what quantities you get that $5 price. Lots and lots would be my guess because that is very cheap for a A8.
Only way I can see it is investing in a lock pick and stealing one. And that's still a maybe lol

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Re: ARMv7 (Cortex-A8)

Sat Oct 04, 2014 11:01 pm

Pointless necro. Locking.
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