{"id":6033,"date":"2024-02-15T16:05:41","date_gmt":"2024-02-15T15:05:41","guid":{"rendered":"https:\/\/www.pschatzmann.ch\/home\/?p=6033"},"modified":"2024-02-17T09:48:59","modified_gmt":"2024-02-17T08:48:59","slug":"stm32f411-discovery-kit-and-arduino-the-i2s-library","status":"publish","type":"post","link":"https:\/\/www.pschatzmann.ch\/home\/2024\/02\/15\/stm32f411-discovery-kit-and-arduino-the-i2s-library\/","title":{"rendered":"STM32F411 Discovery Kit and Arduino: The I2S Library"},"content":{"rendered":"

In my last post<\/a>, I was describing that I started to work on adding I2S audio support to the STM32F411 Discovery Board.<\/p>\n

I finally have my Arduino I2S library<\/a> that supports the STM32F411 Blackpill and Disovery Board<\/strong> ready. I was completely redesigning the old, mostly generated C library into some C++ classes and I have now a better way to support additional boards.<\/p>\n

Unfortunately I still don’t have any clean sound on my Discovery Board: Software Development is not easy!<\/p>\n

Arduino Test Sketch<\/h2>\n

I can use the regular sine generator test sketch that has been written for the AudioKit and is using my flexible driver library<\/a>. I just need to replace the board and use STM32F411Disco<\/strong>.<\/p>\n

#include \"AudioTools.h\"\n#include \"AudioLibs\/AudioBoardStream.h\"\n\nAudioInfo info(44100, 2, 16);\nSineWaveGenerator<int16_t> sineWave(32000);                \/\/ subclass of SoundGenerator with max amplitude of 32000\nGeneratedSoundStream<int16_t> sound(sineWave);             \/\/ Stream generated from sine wave\nAudioBoardStream out(STM32F411Disco);\nStreamCopy copier(out, sound);                             \/\/ copies sound into i2s\n\n\/\/ Arduino Setup\nvoid setup(void) {  \n  \/\/ Open Serial \n  Serial.begin(115200);\n  \/\/while(!Serial);\n  AudioLogger::instance().begin(Serial, AudioLogger::Info);\n\n  \/\/ start I2S\n  Serial.println(\"starting I2S...\");\n  auto config = out.defaultConfig(TX_MODE);\n  config.copyFrom(info); \n  if (!out.begin(config)){\n    Serial.println(\"error!\");\n    stop();\n  }\n\n  \/\/ Setup sine wave\n  sineWave.begin(info, N_B4);\n  Serial.println(\"started...\");\n}\n\n\/\/ Arduino loop - copy sound to out \nvoid loop() {\n  copier.copy();\n}\n\n<\/code><\/pre>\n
So I was checking the I2S pins<\/strong> with an oscilloscope<\/strong> and they look good. Here is output of the clock and data pins:<\/p>\n
\"\"<\/p>\n
The good news is that the data output to the pins seems to work<\/strong>!<\/p>\n
But initially I was not getting any tone: So the issue needs to be with the integration and initialization of the audio chip<\/strong>!<\/p>\n
And I was right: The codec provides a cs43l22_Play method which needs to be called to activate the output. After integrating this into my driver, I am getting some audio output: but unfortunately not the expected clean sine tone (yet).<\/p>\n
So this will be my next task…<\/p>\n
Dependencies<\/h2>\n