SD.rar_write sd card

/*----------------------------------------------- 这里需要用到2G的SD卡，SD卡插上后，会在串口中对数据进行读写。 ------------------------------------------------*/ #include <reg52.h> #include <intrins.h> #include <stdio.h> #include<9325TP.h> //============================================================= //定义SD卡需要的4根信号线 sbit SD_CLK = P1^1; sbit SD_DI = P1^2; sbit SD_DO = P1^0; sbit SD_CS = P1^3; //=========================================================== //定义按键端口 sbit KEY = P3^2; //=========================================================== //定义512字节缓冲区，注意需要使用 xdata关键字 unsigned char xdata DATA[75]={0}; unsigned char xdata DATA1[75]={0}; //=========================================================== //写一字节到SD卡,模拟SPI总线方式 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; } //=========================================================== //从SD卡读一字节,模拟SPI总线方式 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; } //============================================================ //检测SD卡的响应 unsigned char SdResponse() { unsigned char i=0,response; while(i<=8) { response = SdRead(); if(response==0x00) break; if(response==0x01) break; i++; } return response; } //================================================================ //发命令到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卡指定地址写数据,一次最多512字节 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); //两字节CRC校验, 为0XFFFF 表示不考虑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; } //======================================================================= //从SD卡指定地址读取数据,一次最多512字节 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; } /******************************************************************** * 名称 : Com_Init() * 功能 : 初始化串口程序，晶振11.0592, 波特率9600 * 输入 : 无 * 输出 : 无 ***********************************************************************/ void Com_Init(void) { TMOD = 0x20; PCON = 0x00; SCON = 0x50; TH1 = 0xFd; TL1 = 0xFd; TR1 = 1; } //============================================================ //主程序 main() { unsigned long AddTemp=262144;//SD卡地址第一个数据物理地址初始值，可以用winhex查看，这里是512扇区，512x512=262144，根据实际SD卡内容更改 unsigned char i; unsigned char *p; CS=1; delayms(5); RES=0; delayms(5); RES=1; delayms(5); SdInit(); //SD卡初始化 Com_Init(); for(i=0;i<75;i++) { DATA1[i]=i; } SdWriteBlock(DATA1, AddTemp, 75); SdReadBlock(DATA, AddTemp, 75); p= DATA; while(1) for(i=0;i<75;i++) { SBUF = *p+48; while(!TI) //如果发送完毕，硬件会置位TI { _nop_(); } p++; TI = 0; //TI清零 delayms(500); } }