ed at laptop.org
Thu Nov 11 13:57:54 EST 2010
Marvell's Armada SoC family is complicated. There are multiple product lines, and multiple products in each product line, with new ones coming along all the time. So it's hard to nail down just which device is the "latest and greatest" at any time.
OLPC is (unsurprisingly) doing something a little unusual. We're trying to create a laptop (first) and then a tablet, each of which is a really full-function, general-purpose device. If you look at Marvell's ARM product selector guide and try to figure out which SoC is recommended for a laptop, you won't find one. And if you look for tablets you find either (a) SoCs for e-book readers or (b) SoCs for entertainment devices.
Our decision path is based on the obvious criteria of power consumption and cost, but we also need devices that support the interfaces we need as well. There are a lot of devices to connect to an SoC, and the decision tree for finding the SoC that fits well is tricky (mainly because a lot of interfaces may be available, but muxed in a way that makes X unusable if you want to use Y, etc.
In considering performance and cost, we want to look at processors that won't be shiny new when we have a product available, and won't be at the top of the performance curve then, either. The "high-end" SoC of last spring, when we got started, won't be the high-end SoC when a product is available. All of that led us to the Armada 610 product line.
I can't really comment much on the Marvell Mobylize product pages - the one you linked to is one I've never seen before - and they're not really pertinent to what OLPC is doing. Marvell wants to get a lot of vendors using their SoCs in a variety of different ways, so they're motivated to have a variety of sample offerings. In fact, the tablet you pointed to claims to use the Armada 168 SoC, but when you look at http://www.mobylize.org/about the last question says:
"Which Marvell processors are being used with the Moby prototype?
The Moby concept is based on Marvell's high-performance, highly scalable and low-power Marvell® ARMADA™ 610 application processor. Marvell is also making available a reference design for developing and testing applications."
You can get Marvell's spec sheets on the Armada 168 and Armada 610 SoCs at:
P.S. I think I answered the touchscreen questions in my reply to Bert, but yes, we're also using the XO-1 case because that's what we have now. That saves many hundreds of thousands of dollars.
On Nov 11, 2010, at 8:42 AM, NoiseEHC wrote:
> Okay, I will rephrase my questions maybe I will get a real answer to them:
> Is there any reason why do you use the latest and greatest Marvell SoC instead of an old (and maybe cheaper) one? Like the tablets on the "Marvell product platform page" do?
> There were plans for touch screen and bigger display for the XO 1.75. What happened to those plans? Do you use the XO-1 case because there is what you have now, or because those plans were scrapped?
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