ATMEL公司AT89C51SND1为主控制器MP3源代码

				/*H**************************************************************************
				* NAME:         dac_drv.h         
				*----------------------------------------------------------------------------
				* Copyright (c) 2003 Atmel.
				*----------------------------------------------------------------------------
				* RELEASE:      snd1c-refd-nf-4_0_3      
				* REVISION:     1.7     
				*----------------------------------------------------------------------------
				* PURPOSE:
				* This file contains the audio dac driver definitions
				*****************************************************************************/
				
				#ifndef _DAC_DRV_H_
				#define _DAC_DRV_H_
				
				/*_____ I N C L U D E S ____________________________________________________*/
				
				#include "config.h"                         /* system definition */
				#include "board.h"                          /* board definition */
				
				 
				/*_____ M A C R O S ________________________________________________________*/
				
				
				/*_____ D E F I N I T I O N ________________________________________________*/
				
				/*_____ D E C L A R A T I O N ______________________________________________*/
				#ifdef DAC_L3MODE
				extern Byte    mp3_volume;
				
				//#define Dac_emphasis(b)       ((b == TRUE)? (DAC_DEEM = ON) : (DAC_DEEM = OFF))
				#define dac_init()          dac_l3mode_send(DAC_L3I_ADDR,193);
				#define Dac_mute()          dac_l3mode_send(DAC_L3I_ADDR,132);
				#define Dac_unmute()        { dac_set_vol(mp3_volume); dac_l3mode_send(DAC_L3I_ADDR,128); }
				#define Dac_overclock(b)    dac_l3mode_send(DAC_L3I_ADDR+2,b?16+6:32+6);
				
				void dac_set_vol        (Byte volume);
				void dac_l3mode_send    (Byte addr,Byte b);
				
				#else // DAC_L3MODE
				#define Dac_emphasis(b)       ((b == TRUE)? (DAC_DEEM = ON) : (DAC_DEEM = OFF))
				#define Dac_mute()            (DAC_MUTE=ON);
				#define Dac_unmute()          (DAC_MUTE=OFF);
				#ifdef DAC_CLK
				#define Dac_overclock(b)      (DAC_CLK= b);
				#else
				#ifdef DAC_INVCLK
				#define Dac_overclock(b)      (DAC_INVCLK= ~b);
				#endif
				#endif
				#define Dac_set_SF0()         (DAC_SF0= ON);
				#define Dac_set_SF1()         (DAC_SF1= ON);
				#define Dac_clr_SF0()         (DAC_SF0= OFF);
				#define Dac_clr_SF1()         (DAC_SF1= OFF);
				#define dac_init()            ;
				#define dac_set_vol(b)        MP3VOL = MP3VOR = b
				#endif
				
				#endif  /* _DAC_DRV_H_ */