SD卡读写的方式(用SD模式)

SD卡读写的方式(用SD模式) SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?)SD???ÁÐ?µÄ??Ê?(ÓÃSDÄ?Ê?) ??ÎÄÓÉlizequan888??Ï× docÎĵµ?ÉÄÜÔÚWAP?Ëä?ÀÀÌåÑé???Ñ????ÒéÄúÓÅÏÈÑ?ÔñTXT???òÏÂÔØÔ?ÎÄ?þµ????ú?é???? ?ó?Ò?ÁÐ? SD ??ÔõÃ???Óà SD Ä?Ê???Ê??ÁÈ???ÊÇ SPI ??Ê??ÁÈ??òµ?? ÏÂÃæÌùÒ??Î?úÂë??ÊÇÔÚ FPGA ÉÏ?ÌÐò??Ö?ÄÜÓà SD Ä?Ê??øÐÐ?Á??Ã?ÓÐÎÄ?þϵÍ???Ã?ÓÐÓà AVR Ó??þʵÏÖ?? µçÂ?Í??º µçÂ?˵Ã???SD_DAT3 Ò?Ö??ø?ßµçÆ? ?ÌÐò?º #ifndef #define __SD_Card_H__ __SD_Card_H__ #define High 1 #define Low 0 //------------------------------------------------------------------------// SD Card Set I/O Direction DDRX.1 = Low DDRX.1 = High DDRX.2 = Low DDRX.2 = High DDRX.3 = High #define SD_CMD_IN #define SD_CMD_OUT #define SD_DAT_IN #define SD_DAT_OUT #define SD_CLK_OUT // #define SD_DAT3_OUT DDRX.0 = High SD Card Output High/Low PORTX.1 = Low #define SD_CMD_LOW #define SD_CMD_HIGH PORTX.1 = High #define SD_DAT_LOW #define SD_CLK_LOW PORTX.2 = Low PORTX.3 = Low #define SD_DAT_HIGH PORTX.2 = High #define SD_CLK_HIGH PORTX.3 = High #define SD_DAT3_HIGH PORTX.0 = High // SD Card Input Read #define SD_TEST_CMD PINX.1 #define SD_TEST_DAT PINX.2 //------------------------------------------------------------------------#define BYTE #define UINT16 #define UINT32 void Ncr(void); void Ncc(void); BYTE response_R(BYTE); BYTE send_cmd(BYTE *); BYTE SD_read_lba(BYTE *,UINT32,UINT32); BYTE SD_card_init(void); //------------------------------------------------------------------------BYTE read_status; BYTE response_buffer[20]; BYTE RCA[2]; BYTE cmd_buffer[5]; const BYTE cmd0[5] const BYTE cmd2[5] const BYTE cmd3[5] const BYTE cmd7[5] const BYTE cmd9[5] = {0x40,0x00,0x00,0x00,0x00}; = {0x42,0x00,0x00,0x00,0x00}; = {0x43,0x00,0x00,0x00,0x00}; = {0x47,0x00,0x00,0x00,0x00}; = {0x49,0x00,0x00,0x00,0x00}; const BYTE cmd55[5] = {0x77,0x00,0x00,0x00,0x00}; unsigned char unsigned int unsigned long //------------------------------------------------------------------------- const BYTE cmd16[5] = {0x50,0x00,0x00,0x02,0x00}; const BYTE cmd17[5] = {0x51,0x00,0x00,0x00,0x00}; const BYTE acmd6[5] = {0x46,0x00,0x00,0x00,0x02}; const BYTE acmd41[5] = {0x69,0x0f,0xf0,0x00,0x00}; const BYTE acmd51[5] = {0x73,0x00,0x00,0x00,0x00}; //------------------------------------------------------------------------void Ncr(void) { SD_CMD_IN; SD_CLK_LOW; SD_CLK_HIGH; SD_CLK_LOW; SD_CLK_HIGH; } //------------------------------------------------------------------------void Ncc(void) { int i; for(i=0;i<8;i++) { SD_CLK_LOW; SD_CLK_HIGH; } } //------------------------------------------------------------------------BYTE SD_card_init(void) { BYTE x,y; SD_CMD_OUT; SD_DAT_IN; SD_CLK_HIGH; SD_CMD_HIGH; SD_DAT_LOW; read_status=0; for(x=0;x<40;x++) Ncr(); for(x=0;x<5;x++) cmd_buffer[x]=cmd0[x]; y = send_cmd(cmd_buffer); do { for(x=0;x<40;x++); Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd55[x]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(1)>1) //response too long or crc error return 1; Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=acmd41[x]; y = send_cmd(cmd_buffer); Ncr(); } while(response_R(3)==1); Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd2[x]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(2)>1) return 1; Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd3[x]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(6)>1) return 1; RCA[0]=response_buffer[1]; RCA[1]=response_buffer[2]; Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd9[x]; cmd_buffer[1] = RCA[0]; cmd_buffer[2] = RCA[1]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(2)>1) return 1; Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd7[x]; cmd_buffer[1] = RCA[0]; cmd_buffer[2] = RCA[1]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(1)>1) return 1; Ncc(); for(x=0;x<5;x++) cmd_buffer[x]=cmd16[x]; y = send_cmd(cmd_buffer); Ncr(); if(response_R(1)>1) return 1; read_status =1; //sd card ready return 0; } //------------------------------------------------------------------------BYTE SD_read_lba(BYTE *buff,UINT32 lba,UINT32 seccnt) { BYTE c=0; UINT32 i,j; lba+=101; for(j=0;j>15)&0xff; cmd_buffer[2] = (lba>>7)&0xff; cmd_buffer[3] = (lba<<1)&0xff; cmd_buffer[4] = 0; lba++; send_cmd(cmd_buffer); Ncr(); } while(1) { SD_CLK_LOW; SD_CLK_HIGH; if(!(SD_TEST_DAT)) break; } for(i=0;i<512;i++) { BYTE k; for(k=0;k<8;k++) { SD_CLK_LOW; SD_CLK_HIGH; c <<= 1; if(SD_TEST_DAT) c |= 0x01; } *buff=c; buff++; } for(i=0; i<16; i++) { SD_CLK_LOW; SD_CLK_HIGH; } } read_status = 1; return 0; } //SD data next in //------------------------------------------------------------------------BYTE response_R(BYTE s) { BYTE a=0,b=0,c=0,r=0,crc=0; BYTE i,j=6,k; while(1) { SD_CLK_LOW; SD_CLK_HIGH; if(!(SD_TEST_CMD)) break; if(crc++ >100) return 2; } crc =0; if(s == 2) j = 17; for(k=0; k 0) b = response_buffer[k-1]; for(i=0; i<8; i++) { SD_CLK_LOW; if(a > 0) c <<= 1; else i++; a++; SD_CLK_HIGH; if(SD_TEST_CMD) c |= 0x01; if(k > 0) { crc <<= 1; if((crc ^ b) & 0x80) crc ^= 0x09; b <<= 1; crc &= 0x7f; //for crc culcar } } if(s==3) { if( k==1 &&(!(c&0x80))) r=1; } response_buffer[k] = c; } if(s==1 || s==6) { if(c != ((crc<<1)+1)) r=2; } return r; } //------------------------------------------------------------------------BYTE send_cmd(BYTE *in) { int i,j; BYTE b,crc=0; SD_CMD_OUT; for(i=0; i < 5; i++) { b = in[i]; for(j=0; j<8; j++) { SD_CLK_LOW; if(b&0x80) SD_CMD_HIGH; else SD_CMD_LOW; crc <<= 1; SD_CLK_HIGH; if((crc ^ b) & 0x80) crc ^= 0x09; b<<=1; } crc &= 0x7f; } crc =((crc<<1)|0x01); b = crc; for(j=0; j<8; j++) { SD_CLK_LOW; if(crc&0x80) SD_CMD_HIGH; else SD_CMD_LOW; SD_CLK_HIGH; crc<<=1; } return b; } //------------------------------------------------------------------------#endif ÕâÐ??ÌÐòÓÐÐ?ÎÒÒ???Ã??×??Ìù?öÀ?Ï?Íû?ó?ÒÒ?ÆðÌ?ÌÖ??Á????òÆÆÍøÕ? 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