📄 mp3.lst
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410 1 PLLNDIV = 0x7f&NDIV;//set NDIV
411 1 PLLCON |= (0x3&RDIV) << 6;//set RDIV
412 1 PLLRDIV = (0x3ff&RDIV) >> 2;
413 1 //MP3时钟频率的计算方法
414 1 //MP3CLK=PLLCLK/(int)(MPCD+1)负反馈
415 1 MP3CLK |= MPCD;//0000 0010 MPCD=2
416 1 //必须通过计算得到最小 MP3CLK 24M
417 1
418 1 //AUDCLK计算公式
419 1 //AUDCLK=PLLCLK/(int)(AUCD+1)负反馈
420 1 AUDCLK |= AUCD; //AUCD=4 必须通过计算得到 AUDCLK=12.288MHz 1a
421 1
422 1 }
423
424 void MP3Disable(void)
425 { PLLCON |= PLLRES;
426 1 PLLCON &= (~PLLEN);
427 1 MP3CON |= MSKREQ;
C51 COMPILER V7.50 MP3 03/16/2006 09:11:14 PAGE 8
428 1 MP3CON &= (~MPEN);
429 1 AUDCON1 |= 0x20;
430 1 AUDCON1 &= (~0x40);
431 1 AUDCON1 &= (~0x01);
432 1 AUDCON0 = 0x08;
433 1 AUDCON1 = 0xB2;
434 1 AUDDAT = 0xFF;
435 1 }
436 //<<<------------------------by frank----------------------------------------------------
437
438
439 /***Edit by kent***********************************************************/
440 void PllInit(void)
441 {
442 1 if (FirstStart)
443 1 {
444 2 AUXR1 = 0xf2; //这两个寄存器的值在用Start Application和直接上电时不一样,前一种情况下MP3解码器才工作,
445 2 PLLCON = 0; //这里强制将其置为与用Start Application按钮时一致
446 2 FirstStart = 0;
447 2 }
448 1 //锁相环时钟及MP3解码器时钟设置
449 1 CKCON |= X2; //0000 0001使能X2模式,增加处理速度,每个机器周期变成6个振荡周期即3个时钟周期
450 1
451 1 PLLCON &= (~PLLRES);//Enable PLL
452 1 PLLCON |= PLLEN;
453 1 }
454
455 void MP3Init(void)
456 {
457 1
458 1 //MP3音量及音效初始值
459 1 MP3VOR = 0x0f;//0000 1111下同
460 1 MP3VOL = 0x0f;
461 1 MP3BAS = 0x0f;
462 1 MP3MED = 0x0f;
463 1 MP3TRE = 0x0f;
464 1
465 1 //MP3CON自动上电为0011 1111
466 1 MP3CON &= (~MSKREQ); //允许产生MP3中断Clear to allow the MPREQ flag to generate a MP3 interrupt.
467 1 MP3CON |= MPEN; //使能MP3解码器Set to enable the MP3 decoder.
468 1 }
469
470 void AudioInit()
471 { unsigned char i = 10;
472 1 //音频解码器模式及时钟设置
473 1 AUDCON0 = 0x77;//0111 0110
474 1 //AUDCON1 = 0x41;//0100 0111
475 1 AUDCON1 &= (~0xB0);//SRC=0,MSREQ=0,MUDRN=0
476 1 AUDCON1 |= 0x01;
477 1 while (i)i--;
478 1 AUDCON1 |= 0x40;
479 1 }
480
481 void Init(void)
482 {
483 1 PllInit();
484 1 MP3Init();
485 1 AudioInit();
486 1 }
487 /*****Write by kent***************************************************************************************
-/
488 /*PlayInit()函数用来预检MP3歌曲的帧头并作相应的配置*/
C51 COMPILER V7.50 MP3 03/16/2006 09:11:14 PAGE 9
489 void PlayInit(unsigned char *SongName)
490 {
491 1 int i = 0, j = 0, f = 0;
492 1 int k = 0;
493 1 unsigned int total_size;
494 1 //MP3Init();
495 1 //分析MP3信息，可能会比较长，但是没有别的办法
496 1 //先要读出一部分文件内容，大小不能确定
497 1 //while(){
498 1 m = ReadSector(SongName, Page_Buf);//先读出512字节
499 1 ////for(k=0;k<64;k++)printuf("%x ",Page_Buf[k]);
500 1 //when the first 3 bytes are 49 44 33 the next can be 03,this means ID3 V2.3
501 1 if (Page_Buf[0] == 0x49)
502 1 if ((Page_Buf[1] == 0x44) && (Page_Buf[2] == 0x33))
503 1 {
504 2 //search the 7th-10th bytes,use the formular to calculate
505 2 /*计算公式
506 2 int total_size;
507 2 total_size = (Size[0]&0x7F)*0x200000 +(Size[1]&0x7F)*0x4000 +(Size[2]&0x7F)*0x80 +(Size[3]&0x7F)
508 2 */
509 2 total_size = (Page_Buf[6] & 0x7F) * 0x200000 + (Page_Buf[7] & 0x7F) * 0x4000 + (Page_Buf[8] & 0x7F) *
- 0x80 + (Page_Buf[9] & 0x7F);
510 2
511 2 while (total_size > 512)
512 2 {
513 3 ReadSector(SongName, Page_Buf);
514 3 total_size -=512;
515 3 }
516 2
517 2 i = total_size;
518 2 printuf("%x", total_size >> 8);
519 2 printuf("%x\n", total_size & 0xFF);
520 2 }
521 1 //else continue;
522 1
523 1 //search whether the next 1.5bytes are 0xFFF,
524 1 //如果接下来是FFF则为MP3帧头，如果不是则为扩展标签头，需要加10个字节的量
525 1 if (Page_Buf[i] != 0xFF)
526 1 i += 10;
527 1 //for(k=i;k<i+4;k++)printuf("%x ",Page_Buf[k]);
528 1 //get MP3 information from FF FX XX XX 4bytes,and show that
529 1 if ((Page_Buf[i] == 0xFF) && (Page_Buf[i + 1] & 0xF0 == 0xF0))
530 1 {
531 2 MP3_Framehead[0] = Page_Buf[i];
532 2 MP3_Framehead[1] = Page_Buf[i + 1];
533 2 MP3_Framehead[2] = Page_Buf[i + 2];
534 2 MP3_Framehead[3] = Page_Buf[i + 3];
535 2 }
536 1 //printu("The MP3 Framehead Bytes:");
537 1 printuf("%x", MP3_Framehead[0]);
538 1 printuf("%x", MP3_Framehead[1]);
539 1 printuf("%x", MP3_Framehead[2]);
540 1 printuf("%x\n", MP3_Framehead[3]);
541 1 //MP3初始化；
542 1
543 1 if (MP3_Framehead[1] & 0x08)
544 1 {//MP3Disable();//MPEG I
545 2 Init();
546 2 switch ((MP3_Framehead[2] & 0x0C) >> 2)
547 2 {
548 3 case 0x00 : MP3FsInit(24, 126, 3, 5); break;//Fs=44.1kHz
549 3 case 0x01 : MP3FsInit(124, 575, 3, 4); break;//Fs=48kHz
C51 COMPILER V7.50 MP3 03/16/2006 09:11:14 PAGE 10
550 3 case 0x02 : MP3FsInit(124, 511, 3, 9); AUDCON0 = 0x76; break;//Fs=32kHz
551 3 default : break;
552 3 }
553 2 //PLLRegister=PLLCON;
554 2 //MP3Register=MP3CLK;
555 2 //AudioRegister=AUDCLK;
556 2 }
557 1 else
558 1 {//MP3Disable(); //MPEG II
559 2 Init();
560 2 switch ((MP3_Framehead[2] & 0x0C) >> 2)
561 2 {
562 3 case 0x00 : MP3FsInit(24, 126, 3, 11); break;//Fs=22.05kHz
563 3 case 0x01 : MP3FsInit(124, 575, 3, 9); break;//Fs=24kHz
564 3 case 0x02 : MP3FsInit(124, 511, 3, 19); AUDCON0 = 0x76; break;//Fs=16kHz
565 3 default : break;
566 3 }
567 2
568 2 //PLLRegister=PLLCON;
569 2 //MP3Register=MP3CLK;
570 2 //AudioRegister=AUDCLK;
571 2 }
572 1 //printu("The baud rate of now playing song is:");
573 1 printuf("%x \n", BaudRate[1-MP3_Framehead[1] & 0x07][3-MP3_Framehead[1] & 0x06][(MP3_Framehead[2] & 0xF
-0) >> 4-1]);
574 1 //printu("kbps\n");
575 1
576 1 DataRead = 0;//这句一定要加上
577 1 }
578 //播放MP3歌曲*******write by jingxiao*********************************************************************
-****
579 void PlayMP3(unsigned char *SongName)
580 {
581 1 int i =0;
582 1 // while ( 1 ) {
583 1
584 1 while (MP3STA1&MPFREQ)
585 1 {//MP3解码器请求数据块
586 2 m = ReadSector(SongName, Page_Buf);//从当前歌曲中读取512字节
587 2 for (i=0; i<m; i++)
588 2 {
589 3 while (!(MP3STA1 & MPBREQ))
590 3 {//MP3解码器请求数据字节
591 4 while (!PlayState); //暂停播放
592 4 if (ChangeSong)
593 4 {//发生选曲
594 5 DataRead = 0;
595 5 ChangeSong = 0;
596 5 return;
597 5 }
598 4 }
599 3 MP3DAT = Page_Buf[i]; //向MP3解码器数据寄存器送入一个数据字节
600 3 }
601 2
602 2 if (m < 512)
603 2 {//如果从歌曲中读出的数据不足512个字节则结束本歌曲播放
604 3 NowPlaying++;
605 3 MP3InitFlag = 1;
606 3 return;
607 3 }
608 2 }
609 1
C51 COMPILER V7.50 MP3 03/16/2006 09:11:14 PAGE 11
610 1 }
611 //***************************************************************************************************
612
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