/*-----------------------------------------------
  名稱：讀SD卡寫彩屏
  公司：上海浩豚電子科技有限公司
  網站：www.doflye.net
  編寫：師訪
  日期：2009.12
  修改：無
  內容：通過讀出SD卡中320x240像素、16位BMP圖片的HEX數據，依次寫到屏上，還原圖片
  注意事項：由于SD卡使用SPI模式，并且是塊讀取(512Byte),所以需要單片機提供大于512的可用RAM，以供緩沖使用
            這里可以選擇STC89c52RD+、STC89C58RD+、STC89C516RD+，后綴RD+表明擴展RAM是1024字節，RC表明擴展RAM256字節
------------------------------------------------*/
#include <reg52.h>
#include <stdio.h>
#include<9325TP.h>
//=============================================================
//定義SD卡需要的4根信號線
sbit SD_CLK = P1^1;
sbit SD_DI  = P1^2;
sbit SD_DO  = P1^0;
sbit SD_CS  = P1^3;
//===========================================================
//定義按鍵端口
sbit KEY = P3^2;
//===========================================================
//定義512字節緩沖區，注意需要使用 xdata關鍵字
unsigned char xdata DATA[512];

//===========================================================
//寫一字節到SD卡,模擬SPI總線方式
void SdWrite(unsigned char n)
{

unsigned char i;

for(i=8;i;i--)
{
SD_CLK=0;
SD_DI=(n&0x80);
n<<=1;
SD_CLK=1;
}
SD_DI=1; 
} 
//===========================================================
//從SD卡讀一字節,模擬SPI總線方式
unsigned char SdRead()
{
unsigned char n,i;
for(i=8;i;i--)
{
SD_CLK=0;
SD_CLK=1;
n<<=1;
if(SD_DO) n|=1;

}
return n;
}
//============================================================
//檢測SD卡的響應
unsigned char SdResponse()
{
unsigned char i=0,response;

while(i<=8)
{
response = SdRead();
if(response==0x00)
break;
if(response==0x01)
break;
i++;
}
return response;
} 
//================================================================
//發命令到SD卡
void SdCommand(unsigned char command, unsigned long argument, unsigned char CRC)
{

SdWrite(command|0x40);
SdWrite(((unsigned char *)&argument)[0]);
SdWrite(((unsigned char *)&argument)[1]);
SdWrite(((unsigned char *)&argument)[2]);
SdWrite(((unsigned char *)&argument)[3]);
SdWrite(CRC);
}
//================================================================
//初始化SD卡
unsigned char SdInit(void)
{
int delay=0, trials=0;
unsigned char i;
unsigned char response=0x01;

SD_CS=1;
for(i=0;i<=9;i++)
SdWrite(0xff);
SD_CS=0;

//Send Command 0 to put MMC in SPI mode
SdCommand(0x00,0,0x95);


response=SdResponse();

if(response!=0x01)
{
return 0;
} 

while(response==0x01)
{
SD_CS=1;
SdWrite(0xff);
SD_CS=0;
SdCommand(0x01,0x00ffc000,0xff);
response=SdResponse();
} 

SD_CS=1;
SdWrite(0xff);
return 1; 
}
//================================================================
//往SD卡指定地址寫數據,一次最多512字節
unsigned char SdWriteBlock(unsigned char *Block, unsigned long address,int len)
{
unsigned int count;
unsigned char dataResp;
//Block size is 512 bytes exactly
//First Lower SS

SD_CS=0;
//Then send write command
SdCommand(0x18,address,0xff);

if(SdResponse()==00)
{
SdWrite(0xff);
SdWrite(0xff);
SdWrite(0xff);
//command was a success - now send data
//start with DATA TOKEN = 0xFE
SdWrite(0xfe);
//now send data
for(count=0;count<len;count++) SdWrite(*Block++);

for(;count<512;count++) SdWrite(0);
//data block sent - now send checksum
SdWrite(0xff); //兩字節CRC校驗, 為0XFFFF 表示不考慮CRC
SdWrite(0xff);
//Now read in the DATA RESPONSE token
dataResp=SdRead();
//Following the DATA RESPONSE token
//are a number of BUSY bytes
//a zero byte indicates the MMC is busy

while(SdRead()==0);

dataResp=dataResp&0x0f; //mask the high byte of the DATA RESPONSE token
SD_CS=1;
SdWrite(0xff);
if(dataResp==0x0b)
{
//printf("DATA WAS NOT ACCEPTED BY CARD -- CRC ERROR\n");
return 0;
}
if(dataResp==0x05)
return 1;

//printf("Invalid data Response token.\n");
return 0;
}
//printf("Command 0x18 (Write) was not received by the MMC.\n");
return 0;
}

//=======================================================================
//從SD卡指定地址讀取數據,一次最多512字節
unsigned char SdReadBlock(unsigned char *Block, unsigned long address,int len)
{
unsigned int count;
//Block size is 512 bytes exactly
//First Lower SS

 //printf("MMC_read_block\n");

SD_CS=0;
//Then send write command
SdCommand(0x11,address,0xff);

if(SdResponse()==00)
{
//command was a success - now send data
//start with DATA TOKEN = 0xFE
while(SdRead()!=0xfe);

for(count=0;count<len;count++) *Block++=SdRead(); 

for(;count<512;count++) SdRead();

//data block sent - now send checksum
SdRead();
SdRead();
//Now read in the DATA RESPONSE token
SD_CS=1;
SdRead();
return 1;
}
 //printf("Command 0x11 (Read) was not received by the MMC.\n");
return 0;
}

//============================================================
//主程序	
main()
{
 unsigned int x,y; //定義液晶屏坐標
 unsigned long j;  //執行循環需要的臨時變量
  unsigned int i;
  unsigned long AddTemp=393728;//SD卡地址第一個數據物理地址初始值，可以用winhex查看，這里是512扇區，512x512=262144，根據實際SD卡內容更改
  	CS=1;
	delayms(5);
	RES=0;
	delayms(5);
	RES=1;
	delayms(5);
	ILI9325_Initial();//液晶屏初始化
	SdInit();         //SD卡初始化
 while(1)
 {

 for(j=0;j<300;j++)   //300表示一幅圖片含有300x512字節的信息
    {
    SdReadBlock(DATA,AddTemp+(j*512),512);//每次讀出512字節放到緩沖區
    for(i=0;i<256;i++)                    //然后寫到液晶屏，可以顯示256個像素，每個像素16位即2個字節
	   {   
   	   LCD_SetPos(x,x,y,y);
   	   Write_Data(DATA[2*i+1],DATA[2*i]);	 
	   x++;
	   if(x==240)                         //檢測是否寫到屏的邊緣 240x320
	     {
	     y++;
	     x=0;
	     if(y==320)
	       y=0;
	     }
       }
     } 
     AddTemp = AddTemp+((j+20)*512);          //寫完一幅圖片后把SD地址加300x512到下一個圖片地址
     while(KEY);                         //等待按鍵按下繼續執行循環顯示下一幅圖片，如果沒有按下則等待
	 
 } 
}