Diff: main.cpp

Revision:

0:3d6892f6384f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Fri Aug 05 10:07:47 2011 +0000
@@ -0,0 +1,68 @@
+#include "mbed.h"
+#include "SDHCFileSystem.h"
+#include "TLV320.h"
+ 
+TLV320 audio(p9, p10, 52, p5, p6, p7, p8, p29); //TLV320 object
+SDFileSystem sd(p11, p12, p13, p14, "sd");      //SD Card object
+InterruptIn volumeSet(p17);                     
+AnalogIn aIn(p19); 
+FILE *infp;                                     //File pointer object
+/* Buffers */
+int circularBuffer[4096];    
+volatile int readPointer = 0;
+volatile int theta = 0;
+/* Wav file header data, for setting up the transfer protocol */
+short channels;
+long sampleRate;
+short wordWidth;
+/* Function to set volume*/
+void setVolume(void){
+    audio.outputVolume(aIn, aIn);                
+}
+/* Function to read from circular buffer and send data to TLV320 */
+void play(void){ 
+        audio.write(circularBuffer, readPointer, 8);      
+        //Pointer fun :-)
+        readPointer += 8;
+        readPointer &= 0xfff;
+        theta -= 8;
+}
+/* Function to load circular buffer from SD Card */
+void fillBuffer(void){
+    while(!feof(infp)){                                         //fill the circular buffer until the end of the file
+        static volatile int writePointer = 0;
+        if(theta < 4096){
+            fread(&circularBuffer[writePointer], 4, 4, infp);   //read 4 integers into the circular buffer at a time
+            //More pointer fun :D
+            theta+=4;
+            writePointer+=4;
+            writePointer &= 0xfff;
+        }
+    }
+}
+/* main */
+int main(){   
+    infp = fopen("/sd/test.wav", "r");      //open file
+        if(infp == NULL){                   //make sure it's been opened
+        perror("Error opening file!");
+        exit(1);
+    }
+    /* Parse wav file header */
+    fseek(infp, 22, SEEK_SET);                      
+    fread(&channels, 2, 1, infp);
+    fseek(infp, 24, SEEK_SET);
+    fread(&sampleRate, 4, 1, infp);
+    fseek(infp, 34, SEEK_SET);
+    fread(&wordWidth, 2, 1, infp);
+    
+    volumeSet.rise(&setVolume);             //attach set volume function to digital input
+    audio.power(0x07);                      //power up TLV apart from analogue input
+    audio.frequency(sampleRate);            //set sample frequency
+    audio.format(wordWidth, (2-channels));  //set transfer protocol
+    audio.attach(&play);                    //attach interrupt handler to send data to TLV320
+    for(int j = 0; j < 4096; ++j){          //upon interrupt generation
+        circularBuffer[j] = 0;              //clear circular buffer
+    }
+    audio.start(TRANSMIT);                  //interrupt come from the I2STXFIFO only
+    fillBuffer();                           //continually fill circular buffer
+}
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