/Dekrispator_H747

Dekrispator synthesizer for ST Discovery kit STM32H747i

Primary LanguageC

Dekrispator for STM32H747

Hello ! I'm happy (maybe proud ;-)) to share this project with you.
It's once again the Dekrispator infamous synth ported on a powerful dual core mcu development board : Discovery Kit STM32H747I-DISCO from STMicroelectronics.
There's a new instrument called Desynkator which is like three metronomic sound generators synchronized in rational ratios tempi. It shares the same controls and FX as Dekrispator. CC78 enables toggling between the two instruments.
It's an expensive board but I had the opportunity to get one for free, so I could work on a version which would clearly separate USB and audio with the two embedded cores.
Of course, at that cost (about 100€), we can wonder if a raspberry Pi would be a better option (less hassle with hardware configuration) but it's another universe !

More info on this synth here (project started in 2012) : https://github.com/MrBlueXav/Dekrispator_v2/tree/dekrispatorV3

Sound examples for Desynkator :
https://polymerickblue.bandcamp.com/track/desynkator-i
https://polymerickblue.bandcamp.com/track/desynkator-ii

General features :

  • M4 core (at 200 MHz) manages MIDI USB Host function (stable with my old Korg NanoKontrol !). Use CN1 to connect your midi device.

  • M7 core (at 400 MHz) computes sound. Samplerate is 48kHz.

  • Each core communicates through OPENAMP infrastructure. (M4 core just sends midi packets to M7 core.)

  • MIDI Control Changes definitions are in a table of functions "ControlChangeFunctionsTable[128]" in MIDI_application.c file.

  • AUDIO_BUFFER_SIZE is defined in audio_play.h file.

  • No LCD at the moment.

  • LED information :

    • The orange LED reflects the CPU usage : when it's dim CPU gets overloaded.
    • The red LED lights on when sequencer is stopped or when a system error occurs.
    • The green LED indicates a midi usb is connected and recognized.
    • The blue LED indicates midi activity.

  • Debug messages sent with virtual com port from STlink (USART1 --> USB CN2).
    PC Terminal configuration is as follows:
    - BaudRate = 115200 baud
    - Word Length = 8 Bits
    - Stop Bit = 1
    - Parity = None
    - Flow control = None

I encountered endless issues to make this project work and suffered a lot... ;-)) I hope some people will find it useful and could use it as an audio synth platform !
It was first a STM32CubeMX project (the only way I found to reach that point) but can't be regenerated now, be careful ! I left the .ioc file for info only.
You should be able to import the project in STM32CubeIDE, I think all necessary files are in the repository.
Makefiles are in /Release folder with also binaries for direct flashing.

Dekrispator features :

  • monophonic
  • sound generators :
    • oscillators with very low aliased analog waveforms with superb minBLEP oscillators (thanks to Sean Bolton)
    • 4 operators basic FM generator
    • multisaw (several saws with individual "drifters")
    • 10 sine additive generator
    • noise
  • 16 step random sequencer
  • several scales to choose from
  • 2 parallel filters LP/BP/HP with LFOs
  • Effects :
    • vibrato
    • tremolo
    • drive/distortion
    • echo
    • chorus/flanger
    • phaser
  • random sound and FX patch generator

Special thanks : Sean Bolton, Perry R. Cook and Gary P. Scavone, Gabriel Rivas, Ross Bencina, GaryA, Thorsten Klose, erwincoumans, ElectroSmith/DaisySP, ST