Yummy new CPU/GPU combo

Tom Cooksey thomas.cooksey at trolltech.com
Thu Jun 5 13:31:57 CEST 2008

On Thursday 05 June 2008 10:29:36 Andy Green wrote:
> The Glamo offers normal async memory bus interface which we use, but it
> has a bunch of timing constraints.  (There is a synchronous burst bus
> mode that we don't use because the CPU doesn't support it and adding a
> CPLD in there to translate will eat power and doesn't make sense.)
What exactly do you mean by an async memory bus interface? Surely the bus
has a clock to clock data in off the data bus? 

Are you saying that the CPU writes data out at a known frequency and the glamo 
clocks it in at the same frequancy with some UART-like clock sync? This sounds
very, very bad? 

> In addition, we currently slug the Glamo IO with quite heavy wait states
> to get stable operation; without it the Glamo acts weird in ways we
> never got to the bottom of.  A few weeks ago I experimented again with
> reducing these and saw all kinds of framebuffer corruption.  The Glamo
> has several processors in it sharing its internal DRAM (6 or so), I
> guess there is some stuff going on from that direction despite we hold
> the unused ones in reset in there.
> So unless our understanding of that beastie evolves further than the
> datasheets, the current speed of it is what we have to work with.

But it _should_ be an aweful lot faster than it currently is. I understand the reasons 
why it's so slow, but these are hardware bugs. Surely SMedia are the ones who should 
be helping you try and fix those bugs? Or Samsung if it's the CPU. The only bit you've 
done is connect the CPU's bus lines to the Glamo's bus lines - I guess you do that with 
simple copper traces too. There doesn't seem to be a huge amount you can do differently? 

> However like I said when you hold the thing and use it, IMO it's
> perfectly adequate.  The "August" Software Update ;-) has some cool
> alpha and moving things going on that look nice, it's just not so bad as
> you got the impression I believe.

Have you watched the video which started this thread? Seen an iPhone before?
What about the latest Google android videos:

I get so fustrated with people thinking that it's ok for OpenMoko to be worse than
everything else out there. Just because it's open source doesn't mean we can't make
something to thrash the pants off everything else graphicly.

To compete with iPhone, android and everything else which comes along, the OpenMoko
is going to need a programmable 3D pipeline, end of story. IMO, that means an OMAP3,
just like a pandora and just like the beagleboard. I guess FIC is tied to Samsung tho.

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