Porting the project from Arduino IDE to STM32CubeIde

[trx2001]

Hello everyone and thanks to Marcel for sharing this project.

I actually use a STM32F4-Discovery board. If I use the Arduino IDE environment all works fine.
Now I try to port the organ project into STM32CubeIde, and include the CortexM4 ML_SynthTools library on it.
When I compile the project the linker generate an undefined reference for the Organ_Setup() function.

My initialization file is the following:

I think that both Organ_Setup() and STM32F407_AudioInit() functions are implemented into the CortexM4 ML_SynthToools Library.
What I don't understand is why the STM32F407_AudioInit() is recognized while Organ_Setup() not.

Thank in advance
Kind Regards

Luciano

[marcel-licence]

Hello Luciano,

I could imagine that the "extern C" might be missing. The linker needs to know if it should try to link C or C++ functions.

In audio_module.h I put the extern C there:

#ifdef ARDUINO_DISCO_F407VG
extern "C" {
    void STM32F407_AudioInit();
    void STM32F407G_AudioWriteS16(const int16_t *fl_sample, const int16_t *fr_sample);
    void STM32F407G_AudioWrite(const float *fl_sample, const float *fr_sample);
}
#endif

https://github.com/marcel-licence/ML_SynthTools/blob/main/src/ml_organ.h is without extern "C".

You could try to add

extern "C" {
#include "ml_organ.h"
}
#endif

to your code.

In addition to that you could try to cast "SAMPLE_RATE" to float to ensure a type conflict does not cause the linking error.

Hope this helps!
Best regards,
Marcel

[trx2001]

Hi Marcel

I try to insert the extern "C" statement but the compiler fail

My audio source file is already a C file not C++ file

Best Regards
Luciano

[marcel-licence]

I checked the lib. It is the other way around. The Organ_Setup() function is a cpp function. It would be possible to call this from another cpp file. How it works calling from c ... I don't know at the moment. Hope this information helps.

You could try to setup another cpp file which calls the Organ functions. Maybe there is a chance to call your new functions from main.c

[trx2001]

Hi Marcel

I try to convert my main.c to main.cpp and convert program to C++ and the linker work fine.
I prefer to have all in C format

Best Regards

Luciano

[marcel-licence]

You can still write C code.
I tried to convert:

and then just rename main.c to main.cpp.
Compiling and linking works fine in that case.

[trx2001]

Hi Marcel

That's what I did and rearranged other .c file calls and now it compiles correctly.
Thanks a lot for your support

Best Regards

Luciano