mmc._c

采用Mega16＋VS1011B＋SD卡制作的Mp3

# include "iom16v.h"
# include "macros.h"
#include "mmc.h"

//低速模式  //spi low speed
void SPI_Low(void)
{
	SPCR =   BIT(SPE)|BIT(MSTR)|BIT(SPR1)|BIT(SPR0);  //SCK:XTAL-CLOCK/128
	SPSR &= ~BIT(SPI2X);							  //不用倍速
}

//高速模式	//spi full speed
void SPI_High(void)
{
	SPCR =  BIT(SPE)|BIT(MSTR);			//SCK:		XTAL-CLOCK/2，采用倍速  			
	SPSR |= BIT(SPI2X);
}

//端口初始化，模式初始化  //port initialize
void SPI_Init(void)
{
	DDR_INI();
	SPI_High();
}

//写[读]一个字节			//read [and write] one byte
uint8 SPI_WriteByte(register uint8 val)
{
	SPDR = val;
	while(!(SPSR & BIT(SPIF)));	   //等待SPI发送完数据
	return SPDR;
}


//检测SD卡是否插入，已插入，返回1，否则，返回0
uint8 MMC_SD_Detect(void)
{	 
	DDRA&=(~BIT(MMC_SD_INSDETC));   //PA0设置为输入
	//;;//读取MMC_SD_INSDETC，为低电平，表示已经插入SD卡
	;
	if((PINA&=BIT(MMC_SD_INSDETC))==0)
		return 1;
	else
		return 0;
}

//sd卡初始化		//sd card initialize
void MMC_SD_Init(void)
{
	SPI_Init();
	SPI_CS_Deassert();;
}

//sd卡写命令		//sd send command
uint8 MMC_SD_SendCommand(uint8 cmd, uint32 arg)
{
	uint8 r1;
	register uint8 retry=0;
	
	SPI_WriteByte(0xff);
	SPI_CS_Assert();
	
	SPI_WriteByte(cmd | 0x40);//分别写入命令	//send command
	SPI_WriteByte(arg>>24);
	SPI_WriteByte(arg>>16);
	SPI_WriteByte(arg>>8);
	SPI_WriteByte(arg);
	SPI_WriteByte(0x95);
	
	while((r1 = SPI_WriteByte(0xff)) == 0xff)//等待响应，	//wait response
		if(retry++ > 20) break;//超时退出					//time out error

	SPI_CS_Deassert();

	return r1;//返回状态值					//return state
}

//sd卡复位,正常时,返回0
uint8 MMC_SD_Reset(void)
{
	uint8 i;
	register uint8 retry=0;
	uint8 r1=0;
	SPI_Low();
	do
	{
		for(i=0;i<10;i++) SPI_WriteByte(0xff);
		r1 = MMC_SD_SendCommand(0, 0);//发idle命令	//send idle command
		retry++;
		if(retry>10) return 1;//超时退出		//time out
	} while(r1 != 0x01);	


	retry = 0;
	do
	{
		r1 = MMC_SD_SendCommand(1, 0);//发active命令	//send active command
		retry++;
		if(retry>100) return 1;//超时退出		//time out
	} while(r1);
	SPI_High();
	r1 = MMC_SD_SendCommand(59, 0);//关crc		//disable CRC

	r1 = MMC_SD_SendCommand(16, 512);//设扇区大小512	//set sector size to 512
	return 0;//正常返回		//normal return
}

//读一个扇区,成功，返回0
uint8 MMC_SD_ReadSingleBlock(uint32 sector, uint8* buffer)
{
	uint8 r1;
	register uint16 i;
	register uint16 retry=0;

	r1 = MMC_SD_SendCommand(17, sector<<9);//读命令	//read command
	
	if(r1 != 0x00)
		return r1;

	SPI_CS_Assert();
	//等数据的开始	
	while(SPI_WriteByte(0xff) != 0xfe) if(retry++ > 1000){SPI_CS_Deassert(); return 1;}

	for(i=0; i<512; i++)//读512个数据	//read 512 bytes
	{
		*buffer++ = SPI_WriteByte(0xff);
	}

	SPI_WriteByte(0xff);//伪crc
	SPI_WriteByte(0xff);
	
	SPI_CS_Deassert();

	return 0;
}

/*
//写一个扇区		//wirite one sector //not used in this application
uint8 MMC_SD_WriteSingleBlock(uint32 sector, uint8* buffer)
{
	uint8 r1;
	uint16 i;
	uint16 retry=0;

	r1 = MMC_SD_SendCommand(24, sector<<9);//写命令	//send command
	if(r1 != 0x00)
		return r1;

	SPI_CS_Assert();
	
	SPI_WriteByte(0xff);
	SPI_WriteByte(0xff);
	SPI_WriteByte(0xff);

	SPI_WriteByte(0xfe);//发开始符			//send start byte
	
	for(i=0; i<512; i++)//送512字节数据		//send 512 bytes data
	{
		SPI_WriteByte(*buffer++);
	}
	
	SPI_WriteByte(0xff);
	SPI_WriteByte(0xff);
	
	r1 = SPI_WriteByte(0xff);
	
	if( (r1&0x1f) != 0x05)//等待是否成功	//judge if it successful
	{
		SPI_CS_Deassert();
		return r1;
	}
	//等待操作完		//wait no busy
	while(!SPI_WriteByte(0xff))if(retry++ > 2000){SPI_CS_Deassert();return 1;}

	SPI_CS_Deassert();

	return 0;
}

uint32 MMC_SD_ReadCapacity(void)
{
	uint8 r1;
	uint16 i;
	uint16 temp;
	uint8 buffer[16];
	uint32 Capacity;
	//uint8 retry=0;

	r1 = MMC_SD_SendCommand(9, 0);//写命令	//send command  //READ CSD
	if(r1 != 0x00)
		return r1;

	SPI_CS_Assert();
	while(SPI_WriteByte(0xff) != 0xfe);
	
	for(i=0;i<16;i++)
	{
		buffer[i]=SPI_WriteByte(0xff);
	}	

	SPI_WriteByte(0xff);
	SPI_WriteByte(0xff);
	
	SPI_WriteByte(0xff);
	
	SPI_CS_Deassert();

//////////////////////////////////////
//	C_SIZE
	i = buffer[6]&0x03;
	i<<=8;
	i += buffer[7];
	i<<=2;
	i += ((buffer[8]&0xc0)>>6);

///////////////////////////////////////
//  C_SIZE_MULT

	r1 = buffer[9]&0x03;
	r1<<=1;
	r1 += ((buffer[10]&0x80)>>7);


///////////////////////////////////////
// BLOCKNR

	r1+=2;

	temp = 1;
	while(r1)
	{
		temp*=2;
		r1--;
	}
	
	Capacity = ((uint32)(i+1))*((uint32)temp);

/////////////////////////
// READ_BL_LEN

	i = buffer[5]&0x0f;

/////////////////////////
//BLOCK_LEN

	temp = 1;
	while(i)
	{
		temp*=2;
		i--;
	}
/////////////////////////


////////////////////////////////////////////////////////////
//
//  memory capacity = BLOCKNR * BLOCK_LEN
//	
//	BLOCKNR = (C_SIZE + 1)* MULT
//
//           C_SIZE_MULT+2
//	MULT = 2
//
//               READ_BL_LEN
//	BLOCK_LEN = 2
////////////////////////////////////////////////////////////
//The final result

	Capacity *= (uint32)temp;	 
	return Capacity;		
}

*/