Monophonic MIDI-controlled Sound Synthesizer application runs on PIC32MX microcontroller, easily adaptable to other devices.
The "REMI" Synth Module is a monophonic MIDI-controlled sound synthesizer designed primarily for use with electronic wind instument (EWI) MIDI controllers. Provision of a standard 'MIDI IN' port allows the synth to be played by any MIDI controller, for example a keyboard with classic MIDI output. Using a low-cost USB-MIDI adapter/cable, the synth can also be controlled by a computer running music software, for example a MIDI sequencer.
. High quality audio output: 40kHz sample rate, 32-bit precision DSP
. High accuracy oscillator pitch for musical application
. Dual wave-table sound synthesis with mix-ratio modulation (morphing)
. Graphical user interface (2.5" monochrome GLCD, 128x64 pixels) - *optional*
. Command-line interface (CLI) for setup and patching (using PC as terminal)
. Instrument presets (8) selectable from GUI, CLI or MIDI input source
. User-programmable synth patches and wave-table creator (using CLI)
. Noise Generator and Noise Filter (for "pitched noise" effects)
. Effect modulation by breath pressure (CC2) and/or modulation messages (CC1)
. Filter with variable cutoff frequency and resonance, pitch tracking
. Filter frequency control by Expression (CC2), Ampld Env, Mod'n (CC1) or LFO
. Reverberation effect
A PIC32MX on-chip timer module is used to generate a PWM audio output signal. The PWM "DAC" has a resolution of 11 bits, which gives adequate sound quality. For improved sound quality, an optional 12-bit SPI DAC chip may be added. Software DSP computations use 32-bit normalized fixed-point numbers with 20-bit fractional part, allowing the application to run on 32-bit microcontrollers without hardware floating-point capability.
For details of the project, visit the author's web page: http://www.mjbauer.biz/Build_the_REMI_synth.htm
If you need a custom firmware variant, e.g. to support LCD with ST7920 controller, or whatever, send me a request.