Testing I2S on a STM32H7

In my last blogs, I introduced you to the powerfull STM32H743VIT6 microcontroller and demonstrated the analog and PWM audio output using the Arduino Audio Tools library.

I finally managed to extend the stm32-i2s library and so it the time now that I can demonstrate that we can also use I2s as well:

I am using the demo sketch from the AudioTools w/o any changes:

#include "AudioTools.h"

AudioInfo info(44100, 2, 16);
SineWaveGenerator<int16_t> sineWave(32000);                
GeneratedSoundStream<int16_t> sound(sineWave);             
I2SStream out; 
StreamCopy copier(out, sound);                             

// Arduino Setup
void setup(void) {  
  // Open Serial 
  Serial.begin(115200);
  //while(!Serial);
  AudioLogger::instance().begin(Serial, AudioLogger::Info);

  // start I2S
  Serial.println("starting I2S...");
  auto config = out.defaultConfig(TX_MODE);
  config.copyFrom(info); 
  out.begin(config);

  // Setup sine wave
  sineWave.begin(info, N_B4);
  Serial.println("started...");
}

// Arduino loop - copy sound to out 
void loop() {
  copier.copy();
}

Dependencies

The sketch above relies on the following I2S library: https://github.com/pschatzmann/stm32-i2s that needs to be installed separately.

The pins are defined in src/stm32-config-i2s.h:

      {mclk, PC_7, GPIO_AF6_SPI3},\
      {bck, PC_10, GPIO_AF6_SPI3},\
      {ws, PA_4, GPIO_AF6_SPI3},\
      {data_out, PC_12, GPIO_AF6_SPI3},\

Result

The sketch compiles w/o error messages and gives the following information

Sketch uses 81032 bytes (3%) of program storage space. Maximum is 2097152 bytes.
Global variables use 6344 bytes (1%) of dynamic memory, leaving 517944 bytes for local variables. Maximum is 524288 bytes.

Here is result from an oszilloscope for the clock and data out pins:

The library seems to work and we are getting the expected I2S signal!