Freerunner and external Display

Carsten Haitzler (The Rasterman) raster at openmoko.org
Sun May 4 16:09:09 CEST 2008


On Sun, 04 May 2008 08:49:33 -0500 Eric Olson <eric at ericanddebbie.com> babbled:

> Ah darn, but at least it should work for presentations or 
> slideshows...and maybe pong :) if drivers support partial updates.
> 
> Here are some framerate estimates -- feel free to correct me if anything 
> looks off:
> (most devices mention USB 2.0, hopefully they also work with USB 1.1)
> 
> QVGA: max: 13 FPS.
>    Assuming QVGA is supported in hardware/driver.
>    one of rasterman's earlier mails mentioned QVGA
>        is about 320*240*1.5bytes per frame
> 640x480x8bit, max: 5 FPS
>    Some devices mention this mode (640x480x8bits)

1.5 bytes per pixel *IF* its yuv video data. for external display for
presentations u'd be more looking at 2 bytes or 3 (16 or 24bpp) and thus...
8fps or less. qvga is really abysmal for projector display - u'll be looking at
vga minimum for that kind of stuff... and then u're down to 2fps... :)
basically "not worth it".

> Note:  USB 1.1: max: 12 Mbit/sec or 1.5 MBytes per sec
> 
> 
> Here are some resources I found quickly while looking around.  If 
> anybody tries one with the neo or freerunner, let us know.
> http://www.winischhofer.eu/linuxsisusbvga.shtml
> http://www.nslu2-linux.org/wiki/HowTo/AddVGAAdapter
> http://wiki.laptop.org/go/Peripherals/USB_to_VGA
> http://ubuntuforums.org/showthread.php?p=1521295
> 
> 
> Eric
> 
> 
> Carsten Haitzler (The Rasterman) wrote:
> > On Sun, 04 May 2008 12:30:40 +0200 Florian Rebstock
> > <florian.rebstock at gmx.de> babbled:
> > 
> >> Hello,
> >>
> >> what i ever want to know:
> >> could it be possible - to connect the Freerunner with a external VGA
> >> Display or Beamer ?
> >> Because that would be pretty useful for small presentations or so...
> > 
> > basically... no.
> > 
> > u may try a usb vga out but it'll be slowwwww - usb1.1 only. so basically -
> > no, not without extra external hardware and even hen... dubiously useful.
> > 
> > 
> PS
> 
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-- 
Carsten Haitzler (The Rasterman) <raster at openmoko.org>




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