Ben + UBB + a few components = "VGA"

David Kuehling dvdkhlng at gmx.de
Sun Apr 24 04:41:55 EDT 2011


>>>>> "Werner" == Werner Almesberger <werner at almesberger.net> writes:

> This is what it does:
> http://downloads.qi-hardware.com/people/werner/ubb/vga/qvga-out.ogg
> http://downloads.qi-hardware.com/people/werner/ubb/vga/ubb-vga-screenshot.jpg

Hey, this looks good.  Time to give my next powerpoint presentation with
my nanonote :)
[..]
> The "VGA" is if course a li^W^Wmarketing. The horizontal resolution is
> nowhere near real VGA (it's equivalent to 160-320 pixels), but the
> timing is almost correct.

> Color depth is one bit per color. I used all but one signal, so one
> could add one more bit to, say, green. One could probably free another
> bit by multiplexing HSync and VSync.

> The program does a number of evil things, including the disabling of
> interrupts and the display refresh, to gain memory bandwidth and to
> have more predictable timing.

I guess that rules out playing back movies via your VGA?  Hmm, just had
a look at the Jz47xx datasheet, unfortunately we can't make the hw
scaler write all pixels to the same address (else that'd give us a
dma-driven vga output :)

cheers,

David
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