fat.c

5个按键控制+SD卡+MP3程序+MP3电路图

/************************************************************/
         FAT Code for   M32L			
/************************************************************/
#include <iom32v.h>
#include <macros.h>
#include <string.h>
#include "sd.h"
#include "fat.h"

extern uchar BUFFER[512];
unsigned char  LONGNAME_BUFFER_ADDR[30];
unsigned char  DIRNAME_BUFFER_ADDR[30];
unsigned char *LongNameBuffer =		(unsigned char *) LONGNAME_BUFFER_ADDR;
unsigned char *DirNameBuffer =		(unsigned char *) DIRNAME_BUFFER_ADDR;
struct partrecord PartInfo;
unsigned char Fat32Enabled;
unsigned long FirstDataSector;
unsigned int  BytesPerSector;
unsigned int  SectorsPerCluster;
unsigned long FirstFATSector;
unsigned long FirstDirSector;
unsigned long FileSize;
unsigned long FatInCache = 0;

//********************************************************************************************
//读一个扇区
void ReadBlock(unsigned long LBA)
//********************************************************************************************
{   unsigned long temp;
    temp=LBA<<9;
    SD_Read_Block(temp);
}
/*-----------------------------------------------------------------------
 查询数据区一个簇开始扇区号
-----------------------------------------------------------------------*/
unsigned long fatClustToSect(unsigned long clust)
{
	return ((clust-2) * SectorsPerCluster) + FirstDataSector;
}
/*-----------------------------------------------------------------------
 查询一个簇所占扇区数
-----------------------------------------------------------------------*/
unsigned int fatClusterSize(void)
{
	// return the number of sectors in a disk cluster
	return SectorsPerCluster;
}
/*-----------------------------------------------------------------------
查询SD卡文件系统信息
-----------------------------------------------------------------------*/
unsigned char fatInit()
{
    unsigned int data;unsigned char t1,t2;

	struct bpb710 *bpb;
	// 读MBR结构
	ReadBlock(0);  
	// 读取分区表信息
	PartInfo = *((struct partrecord *) ((struct partsector *)BUFFER)->psPart);
	// 读引导扇区
	// 引导扇区号在PartInfo.prStartLBA中
	ReadBlock(PartInfo.prStartLBA);  //ataReadSectors( DRIVE0, PartInfo.prStartLBA, 1, SectorBuffer );
	bpb = (struct bpb710 *) ((struct bootsector710 *) BUFFER)->bsBPB;

	FirstDataSector	= PartInfo.prStartLBA;
	if(bpb->bpbFATsecs)
	{
		// bpbFATsecs非0,为FAT16,FAT表所占的扇区数在bpbFATsecs里
		FirstDataSector	+= bpb->bpbResSectors + bpb->bpbFATs * bpb->bpbFATsecs;
	}
	else
	{
		// bpbFATsecs是0,为FAT32,FAT表所占的扇区数在bpbBigFATsecs里
		FirstDataSector	+= bpb->bpbResSectors + bpb->bpbFATs * bpb->bpbBigFATsecs;
	}
	
	SectorsPerCluster	= bpb->bpbSecPerClust;
	BytesPerSector		= bpb->bpbBytesPerSec;
	FirstFATSector		= bpb->bpbResSectors + PartInfo.prStartLBA;
//查询SD卡文件系统分区类型
	switch (PartInfo.prPartType)
	{
		case PART_TYPE_DOSFAT16:
		case PART_TYPE_FAT16: 
		case PART_TYPE_FAT16LBA:
			// 第一个目录扇区号为2
			FirstDirSector	= CLUST_FIRST;
			//FirstDataSector += (bpb->bpbRootDirEnts)/DIRENTRIES_PER_SECTOR;
			Fat32Enabled = 0;
			
			break;
		case PART_TYPE_FAT32LBA:
		case PART_TYPE_FAT32:
			
			FirstDirSector = bpb->bpbRootClust;
			Fat32Enabled = 1;
			break;
		default:break;
			//return 1;
	}
//查询SD卡文件系统信息
	switch (PartInfo.prPartType)
	{
		case PART_TYPE_DOSFAT16:
				LCD_write_english_string(0,0,"DOSFAT 16");
				break;
		case PART_TYPE_FAT16:
				LCD_write_english_string(0,0,"FAT16 ");
				break;
		case PART_TYPE_FAT16LBA:
				LCD_write_english_string(0,0,"FAT16 LBA");
				break;
		case PART_TYPE_FAT32LBA:
				LCD_write_english_string(0,0,"FAT32 LBA");
				break;
		case PART_TYPE_FAT32:
				LCD_write_english_string(0,0,"FAT32");
				break;
		default:
				LCD_write_english_string(0,0,"No Partition!");
				break;
	}
//显示磁盘容量
data=PartInfo.prSize>>11;
    LCD_set_XY(56,0);
    t1=data/100;
	LCD_write_char(t1+48);
	data=data%100;
	t1=data/10;
	LCD_write_char(t1+48);
	t2=data%10;
	LCD_write_char(t2+48);
	LCD_write_english_string(76,0,"M");
    LCD_write_english_string(0,1,"RATE");
	return 0;	
}

/*-----------------------------------------------------------------------
查询一个文件的开始簇
-----------------------------------------------------------------------*/
unsigned int baseentry = 0;
unsigned int entrycount = 0;


unsigned long fatGetDirEntry(unsigned int entry)
{
	unsigned long sector;
	struct direntry *de = 0;	// 防止compiler warning
	struct winentry *we;
	unsigned int hasBuffer;
	unsigned int b;
	int i,index;
	char *p;
	
		entrycount = 0;
		DirNameBuffer = 0;
	
	
	// 读取目录区数据
	sector = fatClustToSect(FirstDirSector);

	hasBuffer = 0;

	index = 16;	
	do 
	{
		if(index == 16)	// 是否该一人一扇区time for next sector ?
		{
			ReadBlock(sector++);
			de = (struct direntry *)BUFFER;
			index = 0;
		}	
	
		if(*de->deName != 0xE5)
		{
			// 如果if not a deleted entry
			if(de->deAttributes == ATTR_LONG_FILENAME)
			{
				// we have a long name entry
				we = (struct winentry *) de;
				b = 13 *( (we->weCnt-1) & 0x0f);				// index into string
				p = &LongNameBuffer[b];
				for (i=0;i<5;i++)	*p++ = we->wePart1[i*2];	// copy first part			
				for (i=0;i<6;i++)	*p++ = we->wePart2[i*2];	// second part
				for (i=0;i<2;i++)	*p++ = we->wePart3[i*2];	// and third part
				if (we->weCnt & 0x40) *p = 0;					// in case dirnamelength is multiple of 13
				if ((we->weCnt & 0x0f) == 1) hasBuffer = 1;		// mark that we have a long entry
			}
			else
			{
				// we have a short name entry
				// check if this is the end of a multi-part long name entry
				if(hasBuffer)
				{
					// a long entry name has been collected
					// is it a directory ?
					if(de->deAttributes == ATTR_DIRECTORY)
					{
						unsigned long save = FirstDirSector;
						unsigned int save2 = baseentry;
						unsigned long rval;
						
						strcpy(DirNameBuffer,LongNameBuffer);
						strcat(DirNameBuffer,"/");

//						rprintfStr(LongNameBuffer); rprintfProgStrM("/"); //EOL();

						// call recursively
						FirstDirSector = ((unsigned long)de->deHighClust << 16) + de->deStartCluster;
						rval = fatGetDirEntry(entry);
						FirstDirSector = save;
						baseentry = save2;
						if (rval)
							return rval;
						else	
						{
							// reload original sector
							ReadBlock(sector-1);//ataReadSectors( DRIVE0,	sector-1, 1, SectorBuffer);
							entrycount--;			// decrement entry counter		
							*DirNameBuffer = 0;
                 	}
					}
					else // normal file entry
						if(entrycount == entry)		
							break;
					hasBuffer = 0;	// clear buffer	
					entrycount++;	// increment entry counter		
				}
				// else ignore short_name_only entries
			}
		}
		de++;
		index++;
	}	while (*de->deName || index == 16);	// 0 in de->deName[0] if no more entries

	if (hasBuffer == 0)		// end of entries
		return 0;
	
	FileSize = de->deFileSize;
	return (unsigned long) ((unsigned long)de->deHighClust << 16) + de->deStartCluster;
}

/*-----------------------------------------------------------------------
 在FAT表中查询下一个簇所在扇区号
-----------------------------------------------------------------------*/
unsigned long fatNextCluster(unsigned long cluster)
{
	unsigned long nextCluster;
	unsigned long fatMask;
	unsigned long fatOffset;
	unsigned long sector;
	unsigned int offset;
	
	if(Fat32Enabled)
	{
		// 一个表项为4bytes(32 bits)
		fatOffset = cluster << 2;
		// 设置 FAT32 bit mask
		fatMask = FAT32_MASK;
	}
	else
	{
		// 一个表项为2bytes(16 bits)
		fatOffset = cluster << 1;
		// 设置 FAT16 bit mask
		fatMask = FAT16_MASK;
	}
	
	//计算FAT扇区号
	sector = FirstFATSector + (fatOffset / BytesPerSector);
	//计算FAT扇区号中表项的偏移地址
	offset = fatOffset % BytesPerSector;
    
	ReadBlock(sector);

	// 读取下一个簇号
	nextCluster = (*((unsigned long*) &((char*)BUFFER)[offset])) & fatMask;

	// 是否文件的结束簇
	if (nextCluster == (CLUST_EOFE & fatMask))
		nextCluster = 0;
		
	return nextCluster;
}