More progress on my "audio Arduino" prototype: I got FM (frequency modulation) synthesis working a few days ago, but it didn't sound terribly interesting. Then I spent a couple of days building C headers for the STM32F205 processor (libopenstm32 and libmaple don't yet have support). Yawn. Today I returned to FM synthesis and added modulation of the operators, just to make the sound a bit more spicy. Check it out:

Before long (like maybe tomorrow?), I should hook up an input device so I can control parameters liveā€¦