Questions about the cpu to glamo bus and the framebuffer

[Fox Mulder]

Am 07.06.2010 12:37, schrieb Rashid Kratou:
> Hi guys,
> 
> 2 questions.
> 
> First: How "wide" is the bus from the cpu to the glamo gpu? It should be
> clocked with 90 MHz but I read it has only 7,3 MB/s. How is that
> possible? 
> 
> Second: Can I draw directly to the framebuffer. Is it possible in qtmoko
> or in any other distro? I would to write a see programm that just draw
> directly into it. I would like to draw in first frame just every even
> line. And in the second frame only every odd line tosave bandwidth on
> the bus. 
> 
> I don't know if this the right mailing list to ask for it. But maybe you
> can help me :).

If you take a look at the schematics of the freerunner [1] on page 12 is
the glamo multi media coprocessor (not just gpu) shown. It seems that
the data bus is 16Bit wide with 23Bit address bus. It also seems to be
hardwired to use internal PLL for clock generation so i don't know at
which speed it runs.

Ciao,
     Rainer

[1]
http://downloads.openmoko.org/developer/schematics/GTA02/Schematics_Freerunner-GTA02_A5-A7cumulative_public_RC0.pdf