File content as of revision 0:12c56a256ee1:

#include "mbed.h"
#include "max32630fthr.h"
#include "USBSerial.h"
#include "stdio.h"
#include "SDFileSystem.h"

//still needs BITS PER SAMPLE PARSING.
//do this like so: PWM.write(WavValue/2^BPS)

#define BUFFER_SIZE 1024
#define HALF_BUFFER 512

DigitalOut rLED(LED1);
DigitalOut gLED(LED2);
DigitalOut bLED(LED3);

DigitalIn Button(P2_3);

MAX32630FTHR pegasus(MAX32630FTHR::VIO_3V3);
PwmOut PWM(P5_6);
AnalogIn POT(AIN_0);
volatile int bufferPOS = 0;

Serial daplink(P2_1,P2_0);
USBSerial microUSB;
SDFileSystem sd(P0_5, P0_6, P0_4, P0_7, "sd");

int audioDataBuffer[BUFFER_SIZE];

struct WavFile
{
    long int size;
    int channels;
    int sampleRate;
    int bitsPerSample;
};

WavFile Track;

void placeNewSample(void)
{
    //POT.read(); //COMMENTED OUT FOR TESTING
    PWM = (float) audioDataBuffer[bufferPOS]/Track.bitsPerSample; //multiply by POT value for volume.
    bufferPOS = (bufferPOS+1) & 0x07F;
}


int main()
{   

    daplink.printf("\f---DAPLINK SERIAL PORT---\r\n\r\nWAV PLAYER VER 2\r\n\r\n");
    microUSB.printf("micro USB serial port\r\n");
    rLED = LED_ON;
    wait_ms(500);
    rLED = LED_OFF;
    gLED = LED_ON;
    wait_ms(500);
    bLED = LED_ON;
    gLED = LED_OFF;
    
    Ticker SampleTime;
    
    FILE *audio = fopen("/sd/1.wav","r");
    
    if(!audio)
    {
        printf("Failed to open file. [Exit]\r\n");
        return 0;
    }
    
    printf("File opened.\r\n\r\n");
    
    //find file size
    fseek(audio,0L,SEEK_END);
    Track.size = ftell(audio);
    
    printf("File Size:%li \r\n",Track.size);
    
    //read sample rate of wav file
    fseek(audio,22,SEEK_SET);
    fread(audioDataBuffer, 4, 1,audio);
    
    printf("Raw Sample Rate Data: %i\r\n",audioDataBuffer[4]);
    
    Track.channels = audioDataBuffer[0];
    Track.sampleRate =(audioDataBuffer[3] << 8) + audioDataBuffer[2]; //needs to be done due to little-endian encoding of wave file headers
    
    printf("Sample Rate: %i\r\n",Track.sampleRate);
    printf("%i channels \r\n",Track.channels);
    
    //read bits per sample
    fseek(audio,34,SEEK_SET);
    fread(audioDataBuffer, 2, 1,audio);
    Track.bitsPerSample = (audioDataBuffer[1] << 8) + audioDataBuffer[0];
    
    printf("Bits Per Sample: %i\r\n",Track.bitsPerSample);
    
    int flag;
    //find start of actual audio
    fseek(audio,44,SEEK_SET);
    int bytecount;
    bytecount = Track.size;
    
    printf("Size: %i bytes\r\nPlay time: %f minutes",Track.size,(float)((Track.size-44)*8)/Track.bitsPerSample);
    
    //initialize PWM to 1us period [1MHz]
    PWM.period_us(1);
    SampleTime.attach(&placeNewSample,1/(Track.sampleRate));
    //microcontroller may not be strong enough to call fread after attaching a 44.1kHz wav file.
    
    printf("\r\nTicker attached.\r\nRunning Loop...\r\n\r\n");
    
    //take the first block of audio data into the buffer (buffer size is two blocks)
    fread(audioDataBuffer,HALF_BUFFER,1,audio);
    
    int g=0;

    while(ftell(audio) != Track.size)
    {
        printf("Loop %i\f",g++);
        if(bufferPOS < HALF_BUFFER && flag == 0)
        {
            fread(audioDataBuffer + HALF_BUFFER,HALF_BUFFER,1,audio);
            bytecount -= HALF_BUFFER;
            flag = 1;
        }
        else if(bufferPOS >= HALF_BUFFER && flag == 1)
        {
            fread(audioDataBuffer,HALF_BUFFER,1,audio);
            bytecount -= HALF_BUFFER;
            flag = 0;
        }
    }
};