Crude input filtering and FFT analysis.
Connect to front panel over the I2C0 bus.
Fix order of up/down buttons,
Front panel logic for level and frequency knobs, up/down buttons.
UX optimizations to front panel controls.
Fix: don't update parameters to DSP all the time, to avoid resetting
generator.
Replaced FFT window with a flat-top window function. Starting point of a
level analyzer.
Analysis result updates, state machine for interleaved analysis and
configuration update requests.