PolySynth: Minimal 8-Bit Synthesizer

PolySynth comes to life! We can finally generate simple sinusoidal waveforms out of the DAC at arbitrary frequency!

Channel 0 above pulses once per period, so the frequency of that pulse indicates the sine waves' frequency. The above example shows a ~1 kHz sine wave output. The lines DIN, CLK, and CS are the serial interface from the MCU to the DAC. They are toggling much faster than 1kHz (approximately 1 MHz).

To do this, we store sine wave samples in a lookup table and simply iterate through them, streaming them out over SPI at a set frequency.

Now that the hardware drivers are in place, all that is left is to build a firmware stack on top of this to generate multiple frequencies via Additive Sinusoidal Synthesis.

I know not much time has passed since my previous post, but I have the PolySynth boards assembled!!!

They look very nice :) I didn't have any footprint issues; everything is going to plan.

Next step is to develop firmware to do the Additive Fourier Synthesis ...updates to follow.

After weeks of waiting, boards have arrived from Seeed Studio! Look good! :)

I will get them assembled and post when I start testing. Should be very soon.

As of 8/23/2018, PolySynth boards have been ordered! I got 10 from SeeedStudio for cheap, so hopefully they will be of good quality... I've never had a problem before with Seeed, so let's hope they continue to work well for me.

Since this project log update is a few days delayed, the boards should arrive soon! I'll let everyone know when they arrive and I get them assembled.