Audio Digitizer

Audio Digitisation System 🎵

A high-performance audio digitization system built around the STM32F7 microcontroller, featuring dual Delta-Sigma ADCs (PCM1808 and ADAU1978) and an integrated ADC for comprehensive audio capture.

🎯 Overview

This project implements a complete audio digitization pipeline that captures audio data through multiple ADCs and transmits it to a PC for MATLAB-based analysis.

🔧 Hardware Components

STM32F7 Nucleo Board

• Main processing unit
• Handles ADC interfacing and USB communication

PCM1808 Delta-Sigma ADC (Buy)

• Stereo Audio ADC configuration
• Input: Bottom port MEMS microphone from DEVKIT-MEMS-001
• Signal conditioning via AD828 op-amp module (AD828 Module Source)
• I2S interface via SAI1 Block B
• 48 kHz sampling rate
• DMA circular mode operation

Integrated ADC

• Input: Nucleo board pin A3
• Signal from top port MEMS microphone (DEVKIT-MEMS-001)
• Signal conditioning via BOB-09816 (SparkFun BOB-09816)
• Timer-triggered operation
• Circular DMA mode

ADAU1978 Delta-Sigma ADC

• Integrated via STEVAL-STWINMAV1 module
• TDM4 protocol through SAI1 Block A
• 24-bit resolution at 48 kHz
• DMA circular mode operation

Important Note: When configuring SAI for TDM:

• Clock strobing must be set to rising edge
• Frame Synchro offset must be set before the First Bit

🔌 Communication

USB Interface

• Protocol: USB Full Speed (FS) CDC
• Data transmission triggered by user button
• ADC activation controlled via Python script commands

💡 Status Indicators

🛠️ Hardware Sources

Microphones

• DEVKIT-MEMS-001
  • Bottom port MEMS mic → PCM1808
  • Top port MEMS mic → Integrated ADC

Signal Conditioning

• PCM1808: AD828 Op-amp Module
• Integrated ADC: BOB-09816

ADC Modules

• PCM1808 Stereo Delta-Sigma ADC
• STEVAL-STWINMAV1 (ADAU1978)
• STM32F7 Integrated ADC

📝 PCB Documentation

The repository includes:

• STEVAL-STWINMAV1 module adapter designs
• Audio Digitisation Hardware based on PCM1862 (production pending)

📊 Data Analysis

MATLAB scripts are provided for processing the captured audio data. See the /Processing directory for analysis tools.

🤝 Contributing

Contributions are welcome! Please read our Contributing Guide for details on our code of conduct and the process for submitting pull requests.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

✨ Acknowledgments

• STMicroelectronics for the STEVAL-STWINMAV1 reference design
• Same Sky for DEVKIT-MEMS-001
• SparkFun Electronics for BOB-09816
• Contributors and testers

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For technical questions and support, please open an issue in the repository.