Hi all,
I'm having trouble implementing audio output into a TouchGFX application for the STM32F746G-DISCO board.
The TouchGFX part is done, and I also managed to include the necessary files for audio output into the project and call a function to start playing audio.
However, once that function is called, it blocks everything else and the entire board becomes unresponsive. Audio is played in an endless loop and no other interaction is possible.
The nearly exact same question was asked a couple of years ago already, but got no answer because of missing details:
https://community.st.com/s/question/0D50X00009XkdwfSAB/bspaudiooutplay-function-stops-program-execution
So, here are some more details. I've reduced the code as much as possible.
Call hierarchy:
- TouchGFX button press
- Interaction "Call virtual function" --> in the corresponding View.cpp class
- View calls Presenter, Presenter Calls Model
- Model has an include of "myaudio.c" and calls the PlaySound() function
- Class "myaudio.c" then calls the necessary BSP functions
The relevant parts of the class "myaudio.c" are:
#include "main.h"
#include "myaudio.h"
#include "math.h"
static uint16_t audioBuf[4096];
static int PlayerInit()
{
if(BSP_AUDIO_OUT_INIT(OUTPUT_DEVICE_HEADPHONE, 20, 48000) != 0)
{
return -1;
}
else
{
BSP_AUDIO_OUT_SetAudioFrameSlot(CODEC_AUDIOFRAME_SLOT_02);
return 0;
}
}
static int PlaySound()
{
for(int i=0; i<=4094; i+=2)
{
audioBuf[2*i] = 32767.0f + roundf(32767.0f * sinf((2.0f * 3.14159f + 440.0f * (float)i) / 48000));
audioBuf[2*i+1] = 32767.0f + roundf(32767.0f * sinf((2.0f * 3.14159f + 220.0f * (float)i) / 48000));
}
if(BSP_AUDIO_OUT_Play( (uint16_t *) audioBuf, 4096 ) != 0)
{
return -1;
}
else {
return 0;
}
}
The return values are propagated back up to the View, where they are displayed in the UI.
However, none of that happens because the code gets stuck at the BSP_AUDIO_OUT_Play step. Nothing after that gets executed. If I comment it out, everything works fine (but then there is no audio output, obviously).
Where is my mistake, or is this a bug in the audio driver?
Is it intended behaviour of the BSP Play function to play the given audio buffer array in an endless loop? If so, how can it be changed to play a sound only as a one-shot event and then stop?
