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:
http://www.marvell.com/products/processors/applications/armada_100/armada...
http://www.marvell.com/products/processors/applications/armada_600/armada...
- Ed
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:
1.
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?
2.
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?
Thanks!