dac_api.c

凌阳SPCE3200 系统开发板随机自带源程序。共安排了32个子目录

#include ".\Peripheral\DAC\DAC_API.h"

U32 DAC_Get_PCM_Free_Bytes(void);

U16 DAC_TempPCM[DAC_PCM_BUFFER_SIZE];
U32 DAC_temp_rp=0;
U32 DAC_temp_wp=0;
U16 DAC_FIFOArray[4096];
U32 DAC_FIFO_Offset=0;
U8  DAC_FIFOCounter=0;
U8  DAC_Output_Type;
U8  DAC_IRQ_Flag;

#ifdef FOR_DAC_DEBUG
U32 DAC_SampleCount=0;
#endif

void DAC_CheckFIFOEnough(void);

void DAC_FillSoftFIFO(void)
{
	unsigned short TempValue=0;
	unsigned short TempCounter=0;
	unsigned int free_space;

  		if(DAC_Output_Type == Stereo)
		{	
				
			for(TempCounter=0;TempCounter<2048;TempCounter++)
			{
				TempValue = DAC_TempPCM[DAC_temp_rp];
				TempValue ^= 0x8000;
				DAC_FIFOArray[TempCounter+DAC_FIFO_Offset] = TempValue;
			    DAC_temp_rp++;				
				if(DAC_temp_rp == DAC_PCM_BUFFER_SIZE)
					DAC_temp_rp = 0;						
			}
		}
		else if(DAC_Output_Type == Left_Only)
		{
						
			for(TempCounter=0;TempCounter<1024;TempCounter++)	// for stereo
			{
				TempValue = DAC_TempPCM[DAC_temp_rp];
				TempValue ^= 0x8000;
				DAC_FIFOArray[TempCounter*2+DAC_FIFO_Offset] = TempValue;
				DAC_FIFOArray[TempCounter*2+1+DAC_FIFO_Offset] = TempValue;
			    DAC_temp_rp += 2;				 
				if(DAC_temp_rp == DAC_PCM_BUFFER_SIZE)
					DAC_temp_rp = 0;		
			}
		}
		else if(DAC_Output_Type == Right_Only)
		{
			
			for(TempCounter=0;TempCounter<1024;TempCounter++)	// for stereo
			{
				TempValue = DAC_TempPCM[DAC_temp_rp+1];
				TempValue ^= 0x8000;
				DAC_FIFOArray[TempCounter*2+DAC_FIFO_Offset] = TempValue;
				DAC_FIFOArray[TempCounter*2+1+DAC_FIFO_Offset] = TempValue;
				DAC_temp_rp += 2;
				if(DAC_temp_rp == DAC_PCM_BUFFER_SIZE)
					DAC_temp_rp = 0;		
			}
		}
		else if(DAC_Output_Type == MonoToStereo)
		{
			
			for(TempCounter=0;TempCounter<1024;TempCounter++)
			{
				TempValue = DAC_TempPCM[DAC_temp_rp];
				TempValue ^= 0x8000;
				DAC_FIFOArray[TempCounter*2+DAC_FIFO_Offset] = TempValue;
				DAC_FIFOArray[TempCounter*2+1+DAC_FIFO_Offset] = TempValue;
				
				if(DAC_temp_rp!=DAC_temp_wp)
				{
				  DAC_temp_rp++;
				  #ifdef FOR_DAC_DEBUG
                    DAC_SampleCount++;
                  #endif				  
				}
				else
				{
					DAC_temp_rp = DAC_temp_wp;
				}
				
				if(DAC_temp_rp == DAC_PCM_BUFFER_SIZE)
					DAC_temp_rp = 0;						
			}
		}
		else
		{
			//
		}
  	
  	
	if(DAC_FIFOCounter != 0)
	{
		DAC_FIFO_Offset = 0;
		DAC_FIFOCounter = 0;
	}
	else
	{
		DAC_FIFO_Offset += 2048;
		DAC_FIFOCounter = 1;
	}
	
	return;
}


void DAC_Write_PCM_Data(U16 *PCMPtr,U32 PCMSizes) //PCMSizes unit: bytes
{
	U32 i;
	
	for(i=0;i<(PCMSizes/2);i++)
	{
		DAC_TempPCM[DAC_temp_wp++] = PCMPtr[i];
		
		if(DAC_temp_wp == DAC_PCM_BUFFER_SIZE)
		{
			DAC_temp_wp = 0;
		}
	}	
  
	
}


U32 DAC_Get_PCM_Free_Bytes(void)
{
	U32 space;
	
	space = DAC_temp_rp - DAC_temp_wp;
	if(space < 0)
		space += DAC_PCM_BUFFER_SIZE;
	
	if(space == 0)
	{
		return ((DAC_PCM_BUFFER_SIZE*2)-2);
	}
	
	return ((space*2)-2);
}

void DAC_EnableSoftCh(unsigned int Samplerate)
{
	unsigned int TempValue;
	
	DAC_Output_Type=MonoToStereo;
	
	DAC_temp_rp=0;
    DAC_temp_wp=0;
    DAC_FIFO_Offset=0;
    DAC_FIFOCounter=0;	
	
	*P_DAC_BUFFER_SA = 0;
	*P_DAC_FIFOBA_LOW = ((unsigned int)DAC_FIFOArray);			//Set start address of buffer for DAC soft channel
	*P_DAC_FIFOBA_HIGH = ((unsigned int)DAC_FIFOArray) >> 16;

	TempValue = 27000000/Samplerate - 1;					//Set sampling rate of current PCM file
	*P_DAC_SAMPLE_CLK = TempValue;


	*P_DAC_INT_STATUS = 0x4000 | 0x0004 | 0x0003;			//Enable software channel as stereo, 8Kbytes buffer
	*P_DAC_MODE_CTRL2  = (0x0608 | D_VolSel_1 | 0x1003); // for both channel
}

void DAC_CheckFIFOEnough(void)  
{
   DAC_IRQ_Flag=0;
   while(DAC_IRQ_Flag==0);
}
					 

void DAC_DisableSoftCh(void)
{
	*P_DAC_INT_STATUS = 0;					//Stop DAC software channel
	*P_DAC_MODE_CTRL2  = 0;
}