STM32AudioEffects

STM32-Audio-Effects-Unit

Audio effects unit designed for STM32. Includes:

• Library of effects implemented in C (including distortion/overdrive, reverb/echo, and compression)
• Python GUI demo/testbench for effects (based on PyQt, PyPlot, NumPy, and ctypes)
• PCB layout based on STM32F3RETx (plus LTSpice files for select sub-networks)
• CubeMX file for board (including FreeRTOS, peripheral, and pin configuration)
• main.c (FreeRTOS-based firmware)

Firmware features:

• FreeRTOS for task management
• ADC and DAC with DMA for efficient audio processing (note: sample rate = 40.5 kHz)
• I2C for EEPROM and OLED display (coming soon)
• Interrupts/handlers for user inputs

Board includes:

• 1/4" (6.35mm) input/output jacks
• OLED display
• 4 configuration potentiometers + 2 volume potentiometers
• 3 buttons
• 3 switches
• EEPROM (for user configuration backups)
• Input and output active gain and noise filter networks (with LTSpice schematics/simulation files)
• 9V DC wall adapter, 9V battery, and 5V USB power support (converted to 3.3V for Vcc)
• Status and power LEDs

Directory guide:

• /board contains LTSpice files and a KiCad project for the board
• /cubemx contains a CubeMX file for generating code for the MCU configuration and a main.c file containing the FreeRTOS port
• /demo contains files for running the demo
• /effects and /math contain the effects and math libraries
• /signal_gen_tools contains code for generating binary samples files

Running the demo:

1. Copy the contents of /demo to a folder.
2. Install the required modules (at the top of effects.py and main.py)
3. Copy the contents of /math and /effects to the folder from step 1.
4. Compile the C source files using:
5. gcc -Wall -c fast_math.c effects.c
6. Create the shared library using:
7. gcc -shared -o libeffects.dll *.o
8. Add “-m64” if using 64-bit Python
9. Run main.py

A working document for this project (which include requirements, milestones, and technical notes) can be found here.