MAKE: Blog: AVR demo platform rocks the color VGA +audio

AVR demo platform rocks the color VGA +audio

Atmega88Craft

Linus Akesson and friends have created the "Craft" demo - using an ATmega88 to generate 4 channels of 8-bit sound and 3D graphics.

Timing is crucial: One display line takes 24 μs, and is followed by a 7.75 μs break called the horizontal blanking period. After 480 such lines, there's a longer break (1428.75 μs, equal to 45 full display lines) before it all starts over. Two digital signals are used to synchronize the sender (graphics card, custom demo hardware etc.) and the receiver (monitor).
[...]
Sound is generated during the horizontal blanking periods. That gives a sample rate of 31496 kHz. Of course, only the really timing critical part (waveform generation) is performed during the horizontal blanking. Melody, rhythm, amplitude envelopes, arpeggios etc. are handled by a playroutine which gets called once for every video frame, during vertical blanking.

- Craft demo

Related:

Comments

Oldest comments listed first.

Posted by: tester on July 22, 2008 at 7:30 AM

Test comment

testing

Posted by: on July 26, 2008 at 4:48 PM

you guys covered this already....

Posted by: Collin Cunningham on July 27, 2008 at 12:19 AM

where's that?

I searched quite a bit before posting - do recall which entry?

you might be thinking of a similar -

http://blog.makezine.com/archive/2008/07/arduino_vga_demo.html

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