main.cpp

00001 /*This program makes the WAV file of the sinewave in a local file. 
00002 The sampling frequency is 8KHz. In other words, it is the quality of the 
00003 telephone. The quantization precision is 16 bits. You can change the 
00004 frequency of the sinewave, the amplitude by changing a parameter in the 
00005 top of the program. You can change the file name, too. I suggest that 
00006 you make the plain name later. You can listen the wav file which You made 
00007 in Windows Mediaplayer.
00008 */
00009 
00010 /*This program is made in reference to "Sound Programming in C Language" by Aoki Naofumi"*/
00011 
00012 #define FREQ 440 //Frequency (Hz) 
00013 #define AMP 0.5 //Amplitude 0 - 1
00014 #define FILE_NAME "/local/440_05.wav"  //Data file name max 8char.wav fffff_aa.wav
00015 
00016 #include "mbed.h"
00017 #include "TextLCD.h"
00018 
00019 TextLCD lcd(p24, p26, p27, p28, p29, p30);
00020 
00021 LocalFileSystem local("local");
00022 DigitalOut led_1(LED1);
00023 DigitalOut led_2(LED2);
00024 DigitalOut led_3(LED3);
00025 DigitalOut led_4(LED4);
00026 
00027 int main(void)
00028 {
00029   typedef struct
00030   {
00031     int fs;
00032     int bits;
00033     int length;
00034     double *s;
00035   } MONO_PCM;
00036   
00037   FILE *fp;
00038   MONO_PCM pcm;
00039   int i, j;
00040   double s;
00041   short data;
00042   double A, f0;
00043   
00044   char riff_chunk_ID[4];
00045   long riff_chunk_size;
00046   char riff_form_type[4];
00047   char fmt_chunk_ID[4];
00048   long fmt_chunk_size;
00049   short fmt_wave_format_type;
00050   short fmt_channel;
00051   long fmt_samples_per_sec;
00052   long fmt_bytes_per_sec;
00053   short fmt_block_size;
00054   short fmt_bits_per_sample;
00055   char data_chunk_ID[4];
00056   long data_chunk_size;
00057   
00058   lcd.cls();
00059   lcd.locate(0,0);
00060   lcd.printf("Audio wave\n");
00061   
00062   int block_length = 1000;
00063   
00064   pcm.fs = 8000;
00065   pcm.bits = 16;
00066   pcm.length = 40000; //about 5sec
00067   pcm.s = (double*) calloc(block_length, sizeof(double)); 
00068     
00069   A = AMP;
00070   f0 = FREQ;
00071   
00072   if ( NULL == (fp = fopen(FILE_NAME, "wb" )) )
00073     error( "" );
00074   
00075   led_1 = 1;
00076   riff_chunk_ID[0] = 'R';
00077   riff_chunk_ID[1] = 'I';
00078   riff_chunk_ID[2] = 'F';
00079   riff_chunk_ID[3] = 'F';
00080   riff_chunk_size = 36 + pcm.length * 2;
00081   riff_form_type[0] = 'W';
00082   riff_form_type[1] = 'A';
00083   riff_form_type[2] = 'V';
00084   riff_form_type[3] = 'E';
00085   
00086   fmt_chunk_ID[0] = 'f';
00087   fmt_chunk_ID[1] = 'm';
00088   fmt_chunk_ID[2] = 't';
00089   fmt_chunk_ID[3] = ' ';
00090   fmt_chunk_size = 16;
00091   fmt_wave_format_type = 1;
00092   fmt_channel = 1;
00093   fmt_samples_per_sec = pcm.fs;
00094   fmt_bytes_per_sec = pcm.fs * pcm.bits / 8;
00095   fmt_block_size = pcm.bits / 8;
00096   fmt_bits_per_sample = pcm.bits;
00097   
00098   data_chunk_ID[0] = 'd';
00099   data_chunk_ID[1] = 'a';
00100   data_chunk_ID[2] = 't';
00101   data_chunk_ID[3] = 'a';
00102   data_chunk_size = pcm.length * 2;
00103   
00104   fwrite(riff_chunk_ID, 1, 4, fp);
00105   fwrite(&riff_chunk_size, 4, 1, fp);
00106   fwrite(riff_form_type, 1, 4, fp);
00107   fwrite(fmt_chunk_ID, 1, 4, fp);
00108   fwrite(&fmt_chunk_size, 4, 1, fp);
00109   fwrite(&fmt_wave_format_type, 2, 1, fp);
00110   fwrite(&fmt_channel, 2, 1, fp);
00111   fwrite(&fmt_samples_per_sec, 4, 1, fp);
00112   fwrite(&fmt_bytes_per_sec, 4, 1, fp);
00113   fwrite(&fmt_block_size, 2, 1, fp);
00114   fwrite(&fmt_bits_per_sample, 2, 1, fp);
00115   fwrite(data_chunk_ID, 1, 4, fp);
00116   fwrite(&data_chunk_size, 4, 1, fp);
00117   wait(0.5);
00118   led_1 = 0;
00119     
00120   led_2 = 1;
00121   for(i = 0; i < pcm.length/block_length; i++)
00122   {
00123 
00124     for (j = 0; j < block_length; j++)
00125     { 
00126       pcm.s[j] = A * sin(2.0 * 3.141592 * f0 * (i * block_length + j) / pcm.fs);
00127       s = (pcm.s[j] + 1.0) / 2.0 * 65536.0;
00128     
00129       if (s > 65535.0) s = 65535.0; 
00130       else if (s < 0.0) s = 0.0; 
00131     
00132       data = (short)(s + 0.5) - 32768;
00133       fwrite(&data, 2, 1, fp);
00134     }
00135   }
00136   led_2 = 0;
00137   fclose(fp);   
00138   free(pcm.s);
00139   
00140   lcd.locate(0,1);
00141   lcd.printf("Done!\n");
00142   
00143   return 0;
00144 }