SD.rar_SD_SD 8M avr_mega 64 SD_mega64串口程序_proteus 128 sd

/****************************************** * 程序名称: MMC(SD)卡读写程序 * 程序功能: MMC(SD)卡接口操作 ******************************************/ /* INCLUDE参数 */ #include <iom128v.h> #include "mmc.h" /* 全局变量 */ extern unsigned char sector[512]; /************************************ * MMC卡片选-1选中/0不选中 ************************************/ void MMCCS(unsigned char cs) { if(cs==0) PORTB|=(1<<PB0); /* SS=1 */ else PORTB&=~(1<<PB0); /* SS=0 */ } /******************************* * MMC命令发送 *******************************/ unsigned char MMCWrCmd(unsigned char *cmd) { unsigned char i=0,k=0; unsigned char temp=0XFF; MMCCS(0); /* 片选无效 */ spi_send(0XFF); /* 发送8个时钟 */ MMCCS(1); /* 片选有效 */ asm("nop"); for(i=0; i<6; i++) { spi_send(*(cmd++)); /* 发送命令 */ } while(temp==0XFF) { temp = spi_send(0XFF); /* 等待回复 */ if(k++>200) /* 超时返回 */ { return temp; } } return temp; } /******************************* * MMC初始化 *******************************/ unsigned char MMCInit(void) { unsigned int timeout; unsigned char i=0,temp=0; unsigned char cmd[]={0x40,0x00,0x00,0x00,0x00,0x95}; DelayMs(500); /* 发送一定数量的时钟脉冲 */ for(i=0;i<0x10;i++) { spi_send(0XFF); } /* 发送CMD0 */ if(MMCWrCmd(cmd)!=0X01) return 0; /* 发送CMD1 */ cmd[0]=0X41; cmd[5]=0XFF; while(MMCWrCmd(cmd)!=0X00) { if(timeout++>0XFFFE) /* 等待初始化完成 */ return 0; /* 容量大的MMC卡需要用比较长时间 */ } SPIHiSPD(); /* 提高MCU SPI速度 */ return 1; } /******************************* * 读取MMC-CID寄存器 *******************************/ unsigned char MMCCID(void) { unsigned char i; unsigned char cmd[]={0x40,0x00,0x00,0x00,0x00,0xff}; cmd[0]=0X40+10; if(MMCWrCmd(cmd)!=0X00) /* 发送CMD9 */ return 0; /* 读取失败 */ for(i=0;i<16;i++) //uart1_send(spi_send(0XFF)); spi_send(0XFF); return 1; } /******************************* * 读取ONE BLOCK数据 * address-扇区地址 *******************************/ unsigned char MMCRdBolck1(unsigned long address) { unsigned int i; unsigned char temp; unsigned char cmd[]={0x40,0x00,0x00,0x00,0x00,0xff}; cmd[0]=0X40+17; /* READ SINGLE BLOCK */ address=address<<9; /* address*512,取512的整数倍 */ cmd[1]=(address>>24); cmd[2]=(address>>16); cmd[3]=(address>>8); cmd[4]=(address>>0); if(MMCWrCmd(cmd)!=0X00) /* 发送CMD17 */ return 0; /* 读取失败 */ while(spi_send(0XFF)!=0XFE) { asm("nop"); /* 等待数据接受开始，受到0XFE表示开始 */ } for(i=0;i<512;i++) /* 读取数据 */ { sector[i]=spi_send(0XFF); } spi_send(0XFF); /* 取走CRC字节 */ spi_send(0XFF); return 1; } /******************************* * 写ONE BLOCK数据 * address-扇区地址 *******************************/ unsigned char MMCWrBlock1(unsigned long address,unsigned char *buffer) { unsigned int i; unsigned char temp; unsigned char cmd[]={0x40,0x00,0x00,0x00,0x00,0xff}; cmd[0]=0x40+24; /* WRITE SINGLE BLOCK */ address=address<<9; /* address*512,取512的整数倍 */ cmd[1]=(address>>24); cmd[2]=(address>>16); cmd[3]=(address>>8); cmd[4]=(address>>0); if(MMCWrCmd(cmd)!=0X00) /* 发送CMD24 */ return 0; /* 写入失败 */ spi_send(0XFF); /* 发送填冲字节 */ spi_send(0XFE); /* 发送数据开始标志0XFE */ for(i=0;i<512;i++) /* 写入数据 */ { spi_send(sector[i]); } spi_send(0XFF); /* 写入CRC字节 */ spi_send(0XFF); temp=spi_send(0XFF); /* 读取XXX0 0101字节 */ temp=temp&0X1F; if(temp!=0X05) return 0; /* 写入失败 */ while(spi_send(0XFF)==0X00) { asm("nop"); /* BUSY等待 */ } return 1; }