PolyAVR



My attempt in turning an atmega16 microcontroller into a synthesizer. In contrary to other well-known avr synth projects the aim with this one was to create a polyphonic synth able to play simple voices. The final ideal with is work-in-progess piece is to used it as a synth-in-synth kind of way in a diy modular synth.
high-quality sound clip recorded using a looper to layer several sounds
some reverb added, otherwise unprocessed



Schematic and Sourcecode

The PolyAVR is an ongoing project, nevertheless i put first version of the schematic and the accompanying source on this site. The source code is published under GPL, so feel free to re-use and modify it. Right-click the schematic and save to view it at full size.
Some quick info on the tech side of the PolyAVR:
Processor: use an Atmega16, not atmega16L, it needs for clock speed of 16 MHz
Midi:currently midi reception is in omni channel mode
Power Supply: the device needs bipolar (+-12V) power supply, could be modifield for single supply
Ports: Port B and C are used as output, apart from midi in the remaining ports can be freely configured, see schematic for actual configuration
voice assignment: very simple: no new voice is triggered as long as all 4 voice are occupied
pitch: relative pitch is correct, absolute pitch is not
source code:writte in assembler, currently poorly commented

Schematic


Source Code