File content as of revision 0:d6c9b09b4042:

#include "mbed.h"
#include "SDFileSystem.h"
#include "wave_player.h"
#include "Adafruit_LEDBackpack.h"
#include "Adafruit_GFX.h"
#include "rtos.h"
#include "FFT.h"

SDFileSystem sd(p5, p6, p7, p8, "sd"); // SD card

I2C i2c(p28, p27); // LED display 
Adafruit_8x8matrix matrix = Adafruit_8x8matrix(&i2c);

AnalogOut DACout(p18); // speaker
wave_player waver(&DACout);
Mutex speaker_lock;

DigitalOut myled(LED1); // mbed LED

void fft_calc_thread(void const* args) {
    //something
    //pull the array off of sd card
    //vTealfft(arr, 1024);
    while(1) {
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
    }
}

void speaker_thread(void const* args)
{
    while(1)
    {
        // grab file here and put together string
        // string song_title = "/sd/" + "" + ".wav";
        
        FILE *wave_file;
        wave_file=fopen("/sd/africa-toto.wav","r");
        
        speaker_lock.lock();
        waver.play(wave_file);
        speaker_lock.unlock();
        fclose(wave_file);
        Thread::wait(100);
        
    }
}
    

int main()
{
   
    Thread th1(speaker_thread);
    Thread th2(fft_calc_thread);
    
    matrix.begin(0x70);
    while(1) {
        for (int i = 0; i < 8; i++) {
          for (int j = 0; j < 8; j++) {
              matrix.clear();
              matrix.drawPixel(i, j, LED_ON);
              matrix.writeDisplay();  
              wait(.5);
          }
        }
        Thread::wait(100);
    }
    
}