SD卡读写包括两种模式：SD模式和SPI模式。

其中SD模式又可以分为1bit 和4bit两种传输模式。

SD卡缺省使用专有的SD模式。

SD卡规范中主要讲了一些命令，响应和CRC效验等等，整个规范的内容还是很多的。

SD卡上电后，卡处于空闲状态，主机发送CMD0复位SD卡，然后通过CMD55和ACMD41判断当前电压是否在卡的工作范围内。

在得到了正确的响应后，主机可以继续通过CMD10读取SD卡的CID寄存器，通过CMD16设置数据块长度，通过CMD9读取卡的CSD寄存器。

从CSD寄存器中，主机可以获知卡容量，支持的命令集等重要参数。

此时，卡以进入了传输状态，主机就可以通过CMD17/18和CMD24/25对卡进行读写。

CRC校验是为了防止SD卡的命令，应答，数据传输出现错误。

每个命令和应答信号都会产生CRC效验码，每个数据块的传输也会长生CRC效验码。

这段程序是友善之臂推出的mini2440开发板中带的ADS测试源码。

整个阅读代码的过程是对这S3C2440的芯片手册和SD卡规范来看的，对于MMC卡没有给出注释，其实和SD卡是大同小异。

由于是初次接触ARM，对SD规范的认识也不是很深入，再加上自己水平有限，还不能完全读懂源代码，其中的肯定存在一些错误，欢迎大家一起交流讨论。

#define INT 1#define DMA 2int CMD13(void);// Send card statusint CMD9(void);unsigned int*Tx_buffer;//128[word]*16[blk]=8192[byte] unsigned int*Rx_buffer;//128[word]*16[blk]=8192[byte] volatile unsigned int rd_cnt;//读数据计数器volatile unsigned int wt_cnt;//写数据计数器volatile unsigned int block;//读写块总数volatile unsigned int TR_end=0;int Wide=0;// 0:1bit, 1:4bitint MMC=0;// 0:SD , 1:MMCint Maker_ID;char Product_Name[7];int Serial_Num;volatile int RCA;void Test_SDI(void){U32 save_rGPEUP, save_rGPECON;RCA=0;MMC=0;block=3072;//3072Blocks=1.5MByte,((2Block=1024Byte)*1024Block=1MByte)save_rGPEUP=rGPEUP;save_rGPECON=rGPECON;//**配置SD/MMC控制器rGPEUP = 0xf83f;// SDCMD, SDDAT[3:0] => PU En. rGPECON = 0xaaaaaaaa;//SDCMD, SDDAT[3:0]Uart_Printf("\nSDI Card Write and Read Test\n");if(!SD_card_init())//等待SD卡初始化完成return;TR_Buf_new();//发送数据缓冲区初始化Wt_Block();//写卡Rd_Block();//读卡View_Rx_buf();if(MMC)TR_Buf_new();if(MMC){rSDICON |=(1<<5);// YH 0519, MMC Type SDCLKWt_Stream();Rd_Stream();View_Rx_buf();}Card_sel_desel(0);// Card deselectif(!CMD9())Uart_Printf("Get CSD fail!!!\n");rSDIDCON=0;//tark???rSDICSTA=0xffff;rGPEUP=save_rGPEUP;rGPECON=save_rGPECON;}void TR_Buf_new(void)//发送数据缓冲区初始化{//-- Tx & Rx Buffer initializeint i, j;Tx_buffer=(unsigned int*)0x31000000;j=0;for(i=0;i<2048;i++)//128[word]*16[blk]=8192[byte]*(Tx_buffer+i)=i+j;Flush_Rx_buf();}void Flush_Rx_buf(void)//接收数据缓冲区清0{//-- Flushing Rx bufferint i;Rx_buffer=(unsigned int*)0x31800000;for(i=0;i<2048;i++)//128[word]*16[blk]=8192[byte]*(Rx_buffer+i)=0;Uart_Printf("End Rx buffer flush\n");}void View_Rx_buf(){//-- Display Rx bufferint i,error=0;Tx_buffer=(unsigned int*)0x31000000;Rx_buffer=(unsigned int*)0x31800000;Uart_Printf("Check Rx data\n");for(i=0;i<128*block;i++){if(Rx_buffer[i]!= Tx_buffer[i]){Uart_Printf("\nTx/Rx error\n");Uart_Printf("%d:Tx-0x%08x, Rx-0x%08x\n",i,Tx_buffer[i], Rx_buffer[i]);error=1;break;}}if(!error){Uart_Printf("\nThe Tx_buffer is same to Rx_buffer!\n");Uart_Printf("SD CARD Write and Read test is OK!\n");}}void View_Tx_buf(void){}int SD_card_init(void)//SD卡初始化{//-- SD controller & card initializeint i;/* Important notice for MMC test condition *//* Cmd & Data lines must be enabled by pull up resister */rSDIPRE=PCLK/(INICLK)-1;// 400KHzUart_Printf("Init. Frequency is %dHz\n",(PCLK/(rSDIPRE+1)));rSDICON=(1<<4)|1;//先传高位，再传低位，使能CLKrSDIFSTA=rSDIFSTA|(1<<16);//SDI FIFO status register，FIFO复位rSDIBSIZE=0x200;// SDI block size register，设置每块大小为512byte(128word)rSDIDTIMER=0x7fffff;// SDI data / busy timer register，设置超时周期for(i=0;i<0x1000;i++);// 延时，CARD自身初始化需要74个CLKCMD0();//发送CMD0Uart_Printf("In idle\n");//-- Check MMC card OCRif(Chk_MMC_OCR()){Uart_Printf("In MMC ready\n");MMC=1;goto RECMD2;}Uart_Printf("MMC check end!!\n");//-- Check SD card OCRif(Chk_SD_OCR())Uart_Printf("In SD ready\n");else{Uart_Printf("Initialize fail\nNo Card assertion\n");return 0;}RECMD2://检查连接的卡，识别卡的状态rSDICARG=0x0;// CMD2(stuff bit)rSDICCON=(0x1<<10)|(0x1<<9)|(0x1<<8)|0x42;//CMD2为长应答并等待应答,开始发//送CMD2,命令卡发回CID寄存器(保存了生产厂家/时间/批号等等),产生RSP2//检查CMD2是否成功发送并收到响应if(!Chk_CMDend(2, 1))goto RECMD2;//CMD2出错，重新发送rSDICSTA=0xa00;// 清除命令和应答结束标志位Uart_Printf("End id\n");RECMD3://--发送CMD3，给卡分配RCA,rSDICARG=MMC<<16;//CMD3参数， MMC：设置 RCA, SD：请求发RCArSDICCON=(0x1<<9)|(0x1<<8)|0x43;//CMD3为短应答并等待应答,开始发//送CMD3, MMC（设置RCA,产生RSP1）,SD（设置RCA,产生RSP6）//检查CMD3是否成功发送并收到响应if(!Chk_CMDend(3, 1))goto RECMD3;//CMD3出错，重新发送rSDICSTA=0xa00;// 清除命令和应答结束标志位//--Publish RCAif(MMC){RCA=1;rSDIPRE=(PCLK/MMCCLK)-1;Uart_Printf("MMC Frequency is %dHz\n",(PCLK/(rSDIPRE+1)));}else{RCA=( rSDIRSP0 & 0xffff0000 )>>16;//回读RCA,卡被分配RCA后进入//TransferMODE,准备读写Uart_Printf("RCA=0x%x\n",RCA);rSDIPRE=PCLK/(SDCLK)-1;// Normal clock=25MHzUart_Printf("SD Frequency is %dHz\n",(PCLK/(rSDIPRE+1)));}//--State(stand-by) check//根据SD规范，rSDIRSP0高16位存储RCA，低16位存储CARD的状态if(rSDIRSP0 &0x1e00!=0x600 )// 检查CARD状态，不是处于stand-by 状态goto RECMD3;////未就绪，重新发送CMD3Uart_Printf("In stand-by\n");Card_sel_desel(1);// Selectif(!MMC)//若位SD卡，设置4bit的数据传输模式Set_4bit_bus();else//若位MMC卡，设置1bit的数据传输模式Set_1bit_bus();return 1;}void Card_sel_desel(char sel_desel){//-- Card select or deselectif(sel_desel)//选择该卡{RECMDS7://送CMD7表示选择该卡,准备读写,产生RSP1.rSDICARG=RCA<<16;// CMD7参数（RCA,stuff bit)，其中高16位为RCA rSDICCON=(0x1<<9)|(0x1<<8)|0x47;//CMD7为短应答并等待应答,开始发//送CMD7选择该卡,准备读写,产生RSP1//检查CMD7是否成功发送并收到响应if(!Chk_CMDend(7, 1))goto RECMDS7;//出错，重新发送rSDICSTA=0xa00;//清除命令和应答结束标志位//检查是否处于transfer modeif( rSDIRSP0 & 0x1e00!=0x800 )goto RECMDS7;//不处于transfer mode，重新发送CMD7}else//卸载该卡{RECMDD7:rSDICARG=0<<16;// CMD7参数（RCA,stuff bit)，其中高16位为RCA rSDICCON=(0x1<<8)|0x47;// 无应答并,并开始发送CMD7//检查CMD7是否成功if(!Chk_CMDend(7, 0))goto RECMDD7;//失败,重新卸载rSDICSTA=0x800;// //清除命令结束标志位}}void __irq Rd_Int(void)//读中断函数U32 i,status;status=rSDIFSTA;if((status&0x200)== 0x200 )//检查接收FIFO最后是否有数据到来{for(i=(status & 0x7f)/4;i>0;i--){*Rx_buffer++=rSDIDAT;rd_cnt++;}rSDIFSTA=rSDIFSTA&0x200;//清 Rx FIFO Last data Ready标志位}else if((status&0x80)== 0x80 )// 检查Half FULL interrupt标志，只要大于31个字节，就会将该标志置1{for(i=0;i<8;i++){*Rx_buffer++=rSDIDAT;rd_cnt++;}}ClearPending(BIT_SDI);//清零源中断挂起寄存器和中断挂起寄存器}void __irq Wt_Int(void)//写中断函数ClearPending(BIT_SDI);//清零源中断挂起寄存器和中断挂起寄存器rSDIDAT=*Tx_buffer++;wt_cnt++;if(wt_cnt==128*block){rINTMSK |= BIT_SDI;//屏蔽BIT_SDI中断rSDIDAT=*Tx_buffer;TR_end=1;}}void __irq DMA_end(void){ClearPending(BIT_DMA0);//清零源中断挂起寄存器和中断挂起寄存器TR_end=1;}void Rd_Block(void){U32 mode;int status;rd_cnt=0;Uart_Printf("Block read test[ Polling read ]\n");mode = 0 ;rSDIFSTA=rSDIFSTA|(1<<16);// 复位FIFOif(mode!=2)rSDIDCON=(2<<22)|(1<<19)|(1<<17)|(Wide<<16)|(1<<14)|(2<<12)|(block <<0);//YH 040220//设置数据控制寄存器：字传输，块数据传输，4bit数据传输，开始数据传输，数据发送模//式，共读block个块rSDICARG=0x0;// CMD17/18地址参数RERDCMD:switch(mode){case POL:if(block<2)// SINGLE_READ写单块{rSDICCON=(0x1<<9)|(0x1<<8)|0x51;//CMD17为短应答并等待应答,开始发//送CMD17单块读命令，开始读,产生RSP1if(!Chk_CMDend(17, 1))//-- Check end of CMD17goto RERDCMD;//失败，继续发送}else// MULTI_READ，读多块{rSDICCON=(0x1<<9)|(0x1<<8)|0x52;//CMD18为短应答并等待应答,开始发//送CMD18多块读命令，开始读,产生RSP1if(!Chk_CMDend(18, 1))//-- Check end of CMD18goto RERDCMD;//失败，继续发送}rSDICSTA=0xa00;// 清命令和应答结束标志while(rd_cnt<128*block)// 512块个字节{if((rSDIDSTA&0x20)==0x20)// 是否超时{rSDIDSTA=(0x1<<0x5);// 清超时标志位break;}status=rSDIFSTA;if((status&0x1000)==0x1000)// FIFO非空{*Rx_buffer++=rSDIDAT;rd_cnt++;}}break;case INT:pISR_SDI=(unsigned)Rd_Int;rINTMSK =~(BIT_SDI);//屏蔽除所有其他中断rSDIIMSK=5;// 开启Last & Rx FIFO half 中断.if(block<2)// SINGLE_READ{rSDICCON=(0x1<<9)|(0x1<<8)|0x51;//CMD17为短应答并等待应答,开始发//送CMD17单块读命令，开始读,产生RSP1if(!Chk_CMDend(17, 1))//-- Check end of CMD17goto RERDCMD;//失败，继续发送}else// MULTI_READ{rSDICCON=(0x1<<9)|(0x1<<8)|0x52;//CMD18为短应答并等待应答,开始发//送CMD18多块读命令，开始读,产生RSP1if(!Chk_CMDend(18, 1))//-- Check end of CMD18goto RERDCMD;//失败，继续发送}rSDICSTA=0xa00;// 清命令和应答结束标志while(rd_cnt<128*block);rINTMSK |=(BIT_SDI);//屏蔽BIT_SDI中断rSDIIMSK=0;//屏蔽所有中断break;case DMA:pISR_DMA0=(unsigned)DMA_end;rINTMSK =~(BIT_DMA0);rSDIDCON=rSDIDCON|(1<<24);//YH 040227, Burst4 EnablerDISRC0=(int)(SDIDAT);// SDIDATrDISRCC0=(1<<1)+(1<<0);// APB, fixrDIDST0=(U32)(Rx_buffer);// Rx_bufferrDIDSTC0=(0<<1)+(0<<0);// AHB, incrDCON0=(1<<31)+(0<<30)+(1<<29)+(0<<28)+(0<<27)+(2<<24)+(1<<23) +(1<<22)+(2<<20)+128*block;rDMASKTRIG0=(0<<2)+(1<<1)+0;//no-stop, DMA2 channel on, no-swtriggerrSDIDCON=(2<<22)|(1<<19)|(1<<17)|(Wide<<16)|(1<<15)|(1<<14)|(2 <<12)|(block<<0);if(block<2)// SINGLE_READ{rSDICCON=(0x1<<9)|(0x1<<8)|0x51;// sht_resp, wait_resp, dat, start, CMD17if(!Chk_CMDend(17, 1))//-- Check end of CMD17goto RERDCMD;}else// MULTI_READ{rSDICCON=(0x1<<9)|(0x1<<8)|0x52;// sht_resp, wait_resp, dat, start, CMD18if(!Chk_CMDend(18, 1))//-- Check end of CMD18goto RERDCMD;}rSDICSTA=0xa00;// Clear cmd_end(with rsp)while(!TR_end);//Uart_Printf("rSDIFSTA=0x%x\n",rSDIFSTA);rINTMSK |=(BIT_DMA0);TR_end=0;rDMASKTRIG0=(1<<2);//DMA0 stopbreak;default:break;}//-- Check end of DATAif(!Chk_DATend())Uart_Printf("dat error\n");rSDIDCON=rSDIDCON&~(7<<12);rSDIFSTA=rSDIFSTA&0x200;//Clear Rx FIFO Last data Ready, YH 040221 rSDIDSTA=0x10;// Clear data Tx/Rx end detectif(block>1){RERCMD12://--Stop cmd(CMD12)rSDICARG=0x0;//CMD12(stuff bit)rSDICCON=(0x1<<9)|(0x1<<8)|0x4c;//sht_resp, wait_resp, start, CMD12 //-- Check end of CMD12if(!Chk_CMDend(12, 1))goto RERCMD12;rSDICSTA=0xa00;// Clear cmd_end(with rsp)}}void Rd_Stream(void)// only for MMC, 3blk read{int status, rd_cnt=0;if(MMC!=1){Uart_Printf("Stream read command supports only MMC!\n"); return;}Uart_Printf("\n[Stream read test]\n");RECMD11:rSDIDCON=(2<<22)|(1<<19)|(0<<17)|(0<<16)|(1<<14)|(2<<12);rSDICARG=0x0;// CMD11(addr)rSDICCON=(0x1<<9)|(0x1<<8)|0x4b;//sht_resp, wait_resp, dat, start, CMD11while(rd_cnt<128*block){if((rSDIDSTA&0x20)== 0x20 ){Uart_Printf("Rread timeout error");return;}status=rSDIFSTA;if((status&0x1000)==0x1000){//*Rx_buffer++=rSDIDAT;//rd_cnt++;Rx_buffer[rd_cnt++]=rSDIDAT;}}//-- Check end of CMD11if(!Chk_CMDend(11, 1))goto RECMD11;rSDICSTA=0xa00;// Clear cmd_end(with rsp)//-- Check end of DATArSDIDCON=(2<<22)|(1<<19)|(0<<17)|(0<<16);//YH 040220rSDIDCON=rSDIDCON&~(7<<12);//YH 040220, no operation, data readywhile( rSDIDSTA&0x3 !=0x0 );if(rSDIDSTA!=0)Uart_Printf("rSDIDSTA=0x%x\n", rSDIDSTA);rSDIDSTA=0xff;//YH 040221STRCMD12://--Stop cmd(CMD12)rSDICARG=0x0;//CMD12(stuff bit)rSDICCON=(0x1<<9)|(0x1<<8)|0x4c;//sht_resp, wait_resp, start, CMD12//-- Check end of CMD12if(!Chk_CMDend(12, 1))goto STRCMD12;rSDICSTA=0xa00;// Clear cmd_end(with rsp)rSDIFSTA=rSDIFSTA&0x200;//Clear Rx FIFO Last data Ready, YH 040221 Uart_Printf("rSDIFSTA1=0x%x\n", rSDIFSTA);//YH 040221rSDIFSTA=rSDIFSTA&0x200;//Clear Rx FIFO Last data Ready, YH 040221Uart_Printf("rSDIFSTA2=0x%x\n", rSDIFSTA);//YH 040221Uart_Printf("\n--End stream read test\n");}void Wt_Block(void){U32 mode;int status;wt_cnt=0;Uart_Printf("Block write test[ Polling write ]\n");mode = 0 ;rSDIFSTA=rSDIFSTA|(1<<16);//复位FIFOif(mode!=2)rSDIDCON=(2<<22)|(1<<20)|(1<<17)|(Wide<<16)|(1<<14)|(3<<12)|(block <<0);//设置数据控制寄存器：字传输，块数据传输，4bit数据传输，开始数据传输，数据发送模//式，共写block个块rSDICARG=0x0;// CMD24/25地址参数REWTCMD:switch(mode){case POL:if(block<2)// SINGLE_WRITE，写单块{rSDICCON=(0x1<<9)|(0x1<<8)|0x58;//CMD24为短应答并等待应答,开始发//送CMD24单块写命令，开始写,产生RSP1if(!Chk_CMDend(24, 1))//-- Check end of CMD24goto REWTCMD;//命令发送失败}else// MULTI_WRITE，写多块{rSDICCON=(0x1<<9)|(0x1<<8)|0x59;//CMD25为短应答并等待应答,开发//送CMD25多块写命令，开始读写,产生RSP1if(!Chk_CMDend(25, 1))//-- Check end of CMD25goto REWTCMD;//命令发送失败}rSDICSTA=0xa00;// 清命令和应答结束标志while(wt_cnt<128*block){status=rSDIFSTA;if((status&0x2000)==0x2000)//FIFO未满{rSDIDAT=*Tx_buffer++;wt_cnt++;//Uart_Printf("Block No.=%d, wt_cnt=%d\n",block,wt_cnt);}}break;case INT:pISR_SDI=(unsigned)Wt_Int;rINTMSK =~(BIT_SDI);rSDIIMSK=0x10;// Tx FIFO half int.if(block<2)// SINGLE_WRITE{rSDICCON=(0x1<<9)|(0x1<<8)|0x58;//sht_resp, wait_resp, dat, start, CMD24if(!Chk_CMDend(24, 1))//-- Check end of CMD24goto REWTCMD;}else// MULTI_WRITE{rSDICCON=(0x1<<9)|(0x1<<8)|0x59;//sht_resp, wait_resp, dat, start, CMD25if(!Chk_CMDend(25, 1))//-- Check end of CMD25goto REWTCMD;}rSDICSTA=0xa00;// Clear cmd_end(with rsp)while(!TR_end);//while(wt_cnt<128);rINTMSK |=(BIT_SDI);TR_end=0;rSDIIMSK=0;// All maskbreak;case DMA:pISR_DMA0=(unsigned)DMA_end;rINTMSK =~(BIT_DMA0);rSDIDCON=rSDIDCON|(1<<24);//YH 040227, Burst4 EnablerDISRC0=(int)(Tx_buffer);// Tx_bufferrDISRCC0=(0<<1)+(0<<0);// AHB, incrDIDST0=(U32)(SDIDAT);// SDIDATrDIDSTC0=(1<<1)+(1<<0);// APB, fixrDCON0=(1<<31)+(0<<30)+(1<<29)+(0<<28)+(0<<27)+(2<<24)+(1<<23) +(1<<22)+(2<<20)+128*block;//handshake, sync PCLK, TC int, single tx, single service, SDI, H/W request,//auto-reload off, word, 128blk*numrDMASKTRIG0=(0<<2)+(1<<1)+0;//no-stop, DMA0 channel on, no-swtriggerrSDIDCON=(2<<22)|(1<<20)|(1<<17)|(Wide<<16)|(1<<15)|(1<<14)|(3<<1 2)|(block<<0);//YH 040220// Word Tx, Tx after rsp, blk, 4bit bus, dma enable, Tx start, blk numif(block<2)// SINGLE_WRITE{rSDICCON=(0x1<<9)|(0x1<<8)|0x58;//sht_resp, wait_resp, dat, start, CMD24if(!Chk_CMDend(24, 1))//-- Check end of CMD24goto REWTCMD;}else// MULTI_WRITE{rSDICCON=(0x1<<9)|(0x1<<8)|0x59;//sht_resp, wait_resp, dat, start, CMD25if(!Chk_CMDend(25, 1))//-- Check end of CMD25goto REWTCMD;}rSDICSTA=0xa00;// Clear cmd_end(with rsp)while(!TR_end);rINTMSK |=(BIT_DMA0);TR_end=0;rDMASKTRIG0=(1<<2);//DMA0 stopbreak;default:break;}//-- Check end of DATAif(!Chk_DATend())Uart_Printf("dat error\n");rSDIDCON=rSDIDCON&~(7<<12);//YH 040220, Clear Data Transfer mode => no operation, Cleata Data Transfer startrSDIDSTA=0x10;// Clear data Tx/Rx endif(block>1){//--Stop cmd(CMD12)REWCMD12:rSDIDCON=(1<<18)|(1<<17)|(0<<16)|(1<<14)|(1<<12)|(block<<0);//YH 040220rSDICARG=0x0;//CMD12(stuff bit)rSDICCON=(0x1<<9)|(0x1<<8)|0x4c;//sht_resp, wait_resp, start, CMD12 //-- Check end of CMD12if(!Chk_CMDend(12, 1))goto REWCMD12;rSDICSTA=0xa00;// Clear cmd_end(with rsp)//-- Check end of DATA(with busy state)if(!Chk_BUSYend())Uart_Printf("error\n");rSDIDSTA=0x08;//! Should be cleared by writing '1'.}}void Wt_Stream(void)// only for MMC, 3blk write{int status, wt_cnt=0;if(MMC!=1){Uart_Printf("Stream write command supports only MMC!\n");return;}Uart_Printf("\n[Stream write test]\n");RECMD20:rSDIDCON=(2<<22)|(1<<20)|(0<<17)|(0<<16)|(1<<14)|(3<<12);// stream moderSDICARG=0x0;// CMD20(addr)rSDICCON=(0x1<<9)|(0x1<<8)|0x54;//sht_resp, wait_resp, dat, start, CMD20//-- Check end of CMD25if(!Chk_CMDend(20, 1))goto RECMD20;rSDICSTA=0xa00;// Clear cmd_end(with rsp)while(wt_cnt<128*block){status=rSDIFSTA;if((status&0x2000)==0x2000)rSDIDAT=Tx_buffer[wt_cnt++];}//-- Check end of DATAwhile( rSDIFSTA&0x400 );Delay(10);// for the empty of DATA line(Hardware)rSDIDCON=(1<<20)|(0<<17)|(0<<16);//YH 040220rSDIDCON=rSDIDCON&~(7<<12);//YH 040220, no operation, data readywhile((rSDIDSTA&0x3)!=0x0 );if(rSDIDSTA!=0x0)Uart_Printf("rSDIDSTA=0x%x\n", rSDIDSTA);rSDIDSTA=0xff;//Clear rSDIDSTASTWCMD12://--Stop cmd(CMD12)rSDIDCON=(1<<18)|(1<<17)|(0<<16)|(1<<14)|(1<<12);rSDICARG=0x0;//CMD12(stuff bit)rSDICCON=(0x1<<9)|(0x1<<8)|0x4c;//sht_resp, wait_resp, start, CMD12//-- Check end of CMD12if(!Chk_CMDend(12, 1))goto STWCMD12;rSDICSTA=0xa00;// Clear cmd_end(with rsp)//-- Check end of DATA(with busy state)if(!Chk_BUSYend())Uart_Printf("error\n");rSDIDSTA=0x08;Uart_Printf("\n--End Stream write test\n");}int Chk_CMDend(int cmd,int be_resp)//0: Timeout{int finish0;if(!be_resp)// 没有应答信号{finish0=rSDICSTA;//读取SDI command status register，while((finish0&0x800)!=0x800)// 等待命令结束finish0=rSDICSTA;rSDICSTA=finish0;// 清命令结束标志return 1;//成功，返回1}else// 有应答信号{finish0=rSDICSTA;//读取SDI command status register，while(!(((finish0&0x200)==0x200)|((finish0&0x400)==0x400)))//检查超时和应答信号finish0=rSDICSTA;if(cmd==1 | cmd==41)// CRC no check, CMD9 is a long Resp. command.{if((finish0&0xf00)!= 0xa00 )// 命令，应答有错，或超时{rSDICSTA=finish0;// 清错误标志if(((finish0&0x400)==0x400))// 若超时，返回0return 0;}rSDICSTA=finish0;// 清命令和应答结束标志}else// 进行CRC效验{if((finish0&0x1f00)!= 0xa00 )// CRC效验出错{Uart_Printf("CMD%d:rSDICSTA=0x%x, rSDIRSP0=0x%x\n",cmd, rSDICSTA, rSDIRSP0);//输出对应寄存器的值rSDICSTA=finish0;// 清除错误标志位if(((finish0&0x400)==0x400))// 若超时，返回0return 0;}rSDICSTA=finish0;}return 1;}}int Chk_DATend(void){int finish;finish=rSDIDSTA;while(!(((finish&0x10)==0x10)|((finish&0x20)==0x20)))// 检查数据结束和超时位finish=rSDIDSTA;if((finish&0xfc)!= 0x10 )//数据传输结束{Uart_Printf("DATA:finish=0x%x\n", finish);rSDIDSTA=0xec;//清除错误标志return 0;}return 1;}int Chk_BUSYend(void){int finish;finish=rSDIDSTA;while(!(((finish&0x08)==0x08)|((finish&0x20)==0x20)))//检查忙标志位finish=rSDIDSTA;if((finish&0xfc)!= 0x08 ){Uart_Printf("DATA:finish=0x%x\n", finish);rSDIDSTA=0xf4;//清除错误标志return 0;}return 1;}void CMD0(void)//CMD0用于对SD实现软件复位，不论卡处于何种状态，使SD卡处于//空闲状态，等待下一个命令的到来{//-- Make card idle staterSDICARG=0x0;// ，CMD0(stuff bit)rSDICCON=(1<<8)|0x40;// 不等待应答信号，命令开始//并再次发送CMD0 关于cmd0定义：0（start_bit）1（cmd标志）000000（6位cmd编//码）后面是参数（无参数就全0）//-- Check end of CMD0Chk_CMDend(0, 0);// 检查命令是否成功发送rSDICSTA=0x800;// 清除命令结束标志}int Chk_MMC_OCR(void){int i;//-- MMC卡识别的等待操作, 使卡处于空闲状态for(i=0;i<100;i++)//等待的时间取决于厂商{// rSDICARG=0xffc000; //CMD1(MMC OCR:2.6V~3.6V)，设置工作电压rSDICARG=0xff8000;//CMD1(SD OCR:2.7V~3.6V)，设置工作电压rSDICCON=(0x1<<9)|(0x1<<8)|0x41;//CMD1为短应答并等待应答,开始发送CMD1//-- 检查CMD1是否发送成功，并检查卡状态// if(Chk_CMDend(1, 1) & rSDIRSP0==0x80ffc000) //31：忙状态标志位，0表示忙//0xffc000为卡的正常工作电压范围if(Chk_CMDend(1, 1)&&(rSDIRSP0>>16)==0x80ff)//卡处于空闲// if(Chk_CMDend(1, 1) & rSDIRSP0==0x80ff8000)rSDICSTA=0xa00;// 清除命令和应答结束标志位return 1;// 成功}}rSDICSTA=0xa00;//清除命令和应答结束标志位return 0;// 失败}int Chk_SD_OCR(void){int i;//-- SD卡识别的等待操作, 使卡处于空闲状态for(i=0;i<50;i++)// 如果这段时间太短，SD卡的初始化可能会失败{CMD55();//送CMD55,表示下个命令将是特殊功能命令acmd,而非一般命令cmdrSDICARG=0xff8000;//ACMD41(SD OCR:2.7V~3.6V) ，设置工作电压// rSDICARG=0xffc000;//ACMD41(MMC OCR:2.6V~3.6V)设置工作电压rSDICCON=(0x1<<9)|(0x1<<8)|0x69;// ACMD41为短应答并等待应答,开始发//送ACMD41,命令卡发回OCR寄存器(保存了电压参数/busy信号等等),产生//-- 检查ACMD41是否发送成功，并检查卡状态if( Chk_CMDend(41, 1)& rSDIRSP0==0x80ff8000 )//发送成功并且卡处于空闲状态{rSDICSTA=0xa00;//清除命令和应答结束标志位return 1;//成功}Delay(200);//等待卡上电后处于空闲状态}//Uart_Printf("SDIRSP0=0x%x\n",rSDIRSP0);rSDICSTA=0xa00;//清除命令和应答结束标志位return 0;// 失败}int CMD55(void){//CMD55,表示下个命令将是特殊功能acmd,而非一般命令cmdrSDICARG=RCA<<16;//CMD55(RCA,stuff bit)rSDICCON=(0x1<<9)|(0x1<<8)|0x77;//CMD55为短应答(R1)并等待应答,并开始发送CMD55//-- 检查CMD55是成功发送if(!Chk_CMDend(55, 1))return 0;//出错，返回rSDICSTA=0xa00;////清除命令和应答结束标志位return 1;}int CMD13(void)//送CMD13,命令卡的当前状态{int response0;rSDICARG=RCA<<16;// CMD13(RCA,stuff bit)，高16位为RCArSDICCON=(0x1<<9)|(0x1<<8)|0x4d;//CMD13为短应答(R1)并等待应答,并开始发送CMD13//-- Check end of CMD13if(!Chk_CMDend(13, 1))//-- 检查CMD13是成功发送return 0;//出错，返回//Uart_Printf("rSDIRSP0=0x%x\n", rSDIRSP0);if(rSDIRSP0&0x100)//数据是否就绪//Uart_Printf("Ready for Data\n");// else//Uart_Printf("Not Ready\n");response0=rSDIRSP0;response0 &= 0x3c00;response0 = response0 >> 9;//Uart_Printf("Current Status=%d\n", response0);if(response0==6)//卡处于receive data stateTest_SDI();rSDICSTA=0xa00;//清除命令和应答结束标志位return 1;}int CMD9(void)//送CMD9,命令卡发回CSD寄存器(保存了读写参数/卡的容量等内容),产生RSP2{rSDICARG=RCA<<16;// CMD9参数,高16位为RCArSDICCON=(0x1<<10)|(0x1<<9)|(0x1<<8)|0x49;//CMD9为长应答并等待应答,开始发//送CMD9,产生RSP2Uart_Printf("\nCSD register :\n");//-- Check end of CMD9if(!Chk_CMDend(9, 1))// 检查命令是否成功发送return 0;//失败则返回Uart_Printf("SDIRSP0=0x%x\nSDIRSP1=0x%x\nSDIRSP2=0x%x\nSDIRSP3= 0x%x\n", rSDIRSP0,rSDIRSP1,rSDIRSP2,rSDIRSP3);return 1;}void Set_1bit_bus(void)//设置1位数据线{Wide=0;if(!MMC)SetBus();//Uart_Printf("\n****1bit bus****\n");}void Set_4bit_bus(void)//设置4位数据线{Wide=1;SetBus();//Uart_Printf("\n****4bit bus****\n");}void SetBus(void)//设置数据线宽度{SET_BUS:CMD55();//CMD55,表示下个命令将是特殊功能acmd,而非一般命令cmdrSDICARG=Wide<<1;//数据宽度00: 1bit, 10: 4bitrSDICCON=(0x1<<9)|(0x1<<8)|0x46;//ACMD6为短应答(R1)并等待应答,并开始发送// ACMD6设置数据线宽度位4bitif(!Chk_CMDend(6, 1))// 设置失败，则重新设置goto SET_BUS;rSDICSTA=0xa00;//清除命令和应答结束标志位}void Set_Prt(void)//写保护{//-- Set protection addr.0 ~ 262144(32*16*512)Uart_Printf("[Set protection(addr.0 ~ 262144) test]\n"); RECMD28://--Make ACMDrSDICARG=0;// CMD28(addr)rSDICCON=(0x1<<9)|(0x1<<8)|0x5c;//sht_resp, wait_resp, start, CMD28//-- Check end of CMD28if(!Chk_CMDend(28, 1))goto RECMD28;rSDICSTA=0xa00;// Clear cmd_end(with rsp)}void Clr_Prt(void)//清除写保护{//-- Clear protection addr.0 ~ 262144(32*16*512)//Uart_Printf("[Clear protection(addr.0 ~ 262144) test]\n");RECMD29://--Make ACMDrSDICARG=0;// CMD29(addr)rSDICCON=(0x1<<9)|(0x1<<8)|0x5d;//sht_resp, wait_resp, start, CMD29//-- Check end of CMD29。