Ben + UBB + a few components = "VGA"
Werner Almesberger
werner at almesberger.net
Sun Apr 24 02:13:35 EDT 2011
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
(This shows the Jlime desktop. The friendly gentleman in the background
image may be the Muffinman.)
This is what it looks like:
http://downloads.qi-hardware.com/people/werner/ubb/vga/ubb-vga-top.jpg
http://downloads.qi-hardware.com/people/werner/ubb/vga/ubb-vga-conn.jpg
http://downloads.qi-hardware.com/people/werner/ubb/vga/ubb-vga-bottom.jpg
And here is how it works:
http://projects.qi-hardware.com/index.php/p/ben-blinkenlights/source/tree/master/ubb-vga/
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.
- Werner
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