终于实现51单片机读SD卡的逻辑0扇区高兴 -

#include <reg52.h>
#define uchar unsigned char
#define uint unsigned int
sbit p1_7=P1^7;
sbit CS=P2^0; //片选信号（低电平有效）
sbit DATEIN =P2^1;//主-从数据输入
sbit SCLK=P2^2;//时钟信号
sbit DATEOUT=P2^3;//从-主数据输出
uint btime;
uchar c;
sbit led4=P1^0;
sbit led3=P1^1; //2010年12月14日与天津开发区
sbit led2=P1^2;
sbit led1=P1^3;
uchar g=0,s=0,bw=0,q=0; //显示单元个位、十位、百位、千位
uchar code tab1[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e};//不带小数点显示0~9
unsigned char bdata dat;
sbit dat_0=dat^0;
sbit dat_1=dat^1;
sbit dat_2=dat^2;
sbit dat_3=dat^3;
sbit dat_4=dat^4;
sbit dat_5=dat^5;
sbit dat_6=dat^6;
sbit dat_7=dat^7;
bit is_init;//决定是否延时；
uchar lpp;
unsigned char fhz;//返回值
uchar fhz_buff; //读返回值中间量
unsigned char xdata tab[512];
void delay(uint time)
{ while(time)
time--;
}
//**********************************************
/*读sd卡子程序，无返回值，有参函数，参数为要写入DATEIN数据线的字节*/
void write(unsigned char wr_)// 写入一个字节SD卡
{
dat=wr_;
DATEIN=dat_7;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_6;
SCLK=0;
if(!is_init)delay(2);
if(is_init)delay(200);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_5;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_4;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_3;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_2;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_1;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
DATEIN=dat_0;
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=1;
if(is_init) delay(200);
if(!is_init)delay(2);
}
unsigned char read()// 读取一个字节SD卡
{
DATEOUT=1;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_7=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_6=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_5=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_4=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_3=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_2=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_1=DATEOUT;
SCLK=1;
if(is_init)delay(200);
if(!is_init)delay(2);
SCLK=0;
if(is_init)delay(200);
if(!is_init)delay(2);
dat_0=DATEOUT;
return (dat);
}
void restsd()//复位SD卡
{ uchar i;
uchar pcmd[6]={0x40,0x00,0x00,0x00,0x00,0x95};
is_init=1;
CS=1;
for(i=0;i<15;i++)
{
//120时钟
write(0xff);
}
CS=1;
write(0xff);//据说是提高兼容性
CS=0;//片选开
write( pcmd[0]);
write( pcmd[1]);
write( pcmd[2]);
write( pcmd[3]);
write( pcmd[4]);
write( pcmd[5]);
fhz=read();
for(;;)
{
fhz=read();
if(fhz==0x01)break;
}
CS=1;
write(0xff);
}
void initsd()//初始化
{
//
uchar pcmd[6]={0x41,0x00,0x00,0x00,0x00,0xff};//
//
CS=1;
write(0xff);//据说是提高兼容性
CS=0;//片选开
write( pcmd[0]);
write( pcmd[1]);
write( pcmd[2]);
write( pcmd[3]);
write( pcmd[4]);
write( pcmd[5]);
fhz=read();
for(;;)
{
fhz=read();
if(fhz==0x00)break;
}
CS=1;
write(0xff);
}
void readsd()//读SD卡物理扇区
{
uchar pcmd[6]={0x51,0x00,0x01,0xfa,0x00,0xff};//原来这里是高地址字节在前地地址在后啊201012月14日
uint j,n;
CS=1;
write(0xff);//据说是提高兼容性
CS=0;//片选开
write( pcmd[0]);
write( pcmd[1]);
write( pcmd[2]);
write( pcmd[3]);
write( pcmd[4]);
write( pcmd[5]);
DATEOUT=1;
for(;;)
{
fhz=read();
if(fhz==0x00)break;
}
DATEOUT=1;
for(;;)
{
fhz=read();
if(fhz==0xfe)break;
}
DATEOUT=1;
n=0;
for(j=512;j;j--)
{
tab[n]=read();
n++;
}
fhz=read();
fhz=read();
CS=1;
write(0xff);
}
/*void writesd()
{
uchar pcmd[6]={0x58,0x00,0x00,0x00,0x00,0xff};
uint j,k;
CS=1;
write(0xff);//据说是提高兼容性
CS=0;//片选开
write( pcmd[0]);
write( pcmd[1]);
write( pcmd[2]);
write( pcmd[3]);
write( pcmd[4]);
write( pcmd[5]);
DATEOUT=1;
for(;;)
{
fhz=read();
if(fhz==0x00)break;
}
DATEOUT=1;
for(j=20;j;j--)
{
write(0xff);
}
write(0xfe);
for(j=512;j;j--)
{ k=tab[j];
write(k);
}
write(0xff);
write(0xff);
DATEOUT=1;
for(;;)
{
fhz=read();
if((fhz&0x0f)==0x05)break;
}
if(!DATEOUT);
{
write(0xff);
}
CS=1;
write(0xff);
}
*/
void delay1(uint z) //延时程序
{
uint x,a,b;
for (x=0;x<z;x++)
{
for(b=120;b>0;b--)
{
for(a=3;a>0;a--);
}
}
}
void display(uchar sd) //显示程序
{
c=sd;
g=(sd&0x0f);
c=(c>>4);
s=(c&0x0f);
led1=0;
P0=tab1[g]; //个
delay1(2);
led1=1;
led2=0;
P0=tab1[s];//十
delay1(2);
led2=1;
led3=0;
P0=tab1[0]; //百
delay1(2);
led3=1;
led4=0;
P0=tab1[0]; //千
delay1(2);
led4=1;
}
void delay2(void) //误差 -0.00000000025us
{
unsigned char a,b,c,n;
for(c=217;c>0;c--)
for(b=225;b>0;b--)
for(a=225;a>0;a--);
for(n=10;n>0;n--);
}
void main()
{ uint ad;
uchar v;
is_init=1;
restsd();
initsd();
is_init=0;//提高始终频率
p1_7=0;
//writesd();
readsd();//读物理扇区
p1_7=1;
btime=65536;
while(1)
{ btime=300;
delay2();
for(;;)
{
v=tab[ad];
display(v);
btime--;
if(btime==0)break;
}
ad++;
if(ad==512)ad=0;
}
}

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