alexxnica / dekrispator

Experimental Music synthesizer based on an STM32F4 Discovery board (ARM Cortex M4F from STM32 series) with USB MIDI Host function for interaction and automatic mode.

Dekrispator

////// Please check now Dekrispator_v2 repository for new STM32F4Cube HAL based version. //////

Transform your STM32F4 Discovery board into an experimental music synthesizer or autonomous noise box with USB MIDI Host function for interaction !

The sound demos are here : https://soundcloud.com/bluexav

A video is here : http://youtu.be/fcLrcDCaI7w

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Usage

Flash your board with "dekrispator.hex" (in Release folder) and enjoy hours and hours of sweet music coming of it ! Sounds can be loud so beware !

When powering up the board, the synth starts in "demo mode" unless you press and maintain a little the user button before power. In that case the synth enters "user mode".

Demo mode : The synth works on its own, sounds are perpetually changing. If you press the user button, sounds and effects stop always changing and the red LED lights on : the synth parameters are frozen. Press once again the user button and the red LED lights off : unfreeze.

User mode : Connect an USB MIDI controller (like Korg NanoKontrol...) to the board's micro USB connector and control the synth. The MIDI mapping of the synth controls are in MIDI_mapping.ods file. I nearly used the factory settings of Korg NanoKontrol V1 (some momentary/toggle buttons modified).

The MIDI USB Host driver is rudimentary and has still some issues !

The orange LED reflects the CPU usage : when it's dim CPU gets overloaded.

Ready to use files are in Ressources folder.

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Dekrispator features :

• monophonic
• all digital !
• oscillators with :
• very low aliased analog waveforms with minBLEP oscillators (thanks Sean Bolton)
• 4 OP FM generator
• multisaw (several saws with individual "drifters")
• 10 sine additive generator
• noise
• vibrato
• tremolo
• drive/distortion
• 16 step random sequencer
• several scales to choose from
• 2 parallel filters LP/BP/HP with LFOs
• Effects :
• Echo
• Chorus/Flanger
• Phaser
• random sound/FX patch generator

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Building from source :

I've used (Windows):

• Eclipse Kepler
• GNU ARM plugin for Eclipse
• Yagarto tools for make, rm, ...
• GNU Tools for ARM Embedded Processors (gcc 4.8 2013 q4)
• STM32 ST-LINK Utility for flashing the microcontroller

Simple command line :
Go into Release folder and type make (with Cygwin terminal).

Compiles also on Linux (Ubuntu 12.04 LTS) !

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See also the port to Windows, Linux, Mac and Raspberry Pi by erwincoumans :

https://github.com/erwincoumans/StkDekrispatorSynthesizer