51+ch375.htm

51+ch375读写U盘超精简原程序

        0; mBlockCount -- ) {<BR>&nbsp;&nbsp;&nbsp;&nbsp;c = mWaitInterrupt( 
        );&nbsp;&nbsp;/* 等待中断并获取状态 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;if ( c == 
        USB_INT_DISK_READ ) {&nbsp;&nbsp;/* 等待中断并获取状态,请求数据读出 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CH375_WR_CMD_PORT( 
        CMD_RD_USB_DATA );&nbsp;&nbsp;/* 从CH375缓冲区读取数据块 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c = CH375_RD_DAT_PORT( 
        );&nbsp;&nbsp;/* 后续数据的长度 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;while 
        ( c -- ) *oDataBuffer++ = CH375_RD_DAT_PORT( 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CH375_WR_CMD_PORT( 
        CMD_DISK_RD_GO );&nbsp;&nbsp;/* 继续执行USB存储器的读操作 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;else 
        break;&nbsp;&nbsp;/* 返回错误状态 */<BR>&nbsp;&nbsp;}<BR>&nbsp;&nbsp;if ( 
        mBlockCount == 0 ) {<BR>&nbsp;&nbsp;&nbsp;&nbsp;c = mWaitInterrupt( 
        );&nbsp;&nbsp;/* 等待中断并获取状态 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;if ( c== 
        USB_INT_SUCCESS ) return( 0 );&nbsp;&nbsp;/* 操作成功 
        */<BR>&nbsp;&nbsp;}<BR>&nbsp;&nbsp;return( c );&nbsp;&nbsp;/* 操作失败 
        */<BR>}<BR><BR>/* ********** FAT文件系统层,这层程序量实际较大,不过,该程序仅演示极简单的功能,所<BR>以精简 
        */<BR><BR>UINT16&nbsp;&nbsp;mGetPointWord( UINT8X *iAddr ) 
        {&nbsp;&nbsp;/* 获取字数据,因为MCS51是大端格式 */<BR>&nbsp;&nbsp;return( iAddr[0] | 
        (UINT16)iAddr[1] &lt;&lt; 8 );<BR>}<BR><BR>UINT8&nbsp;&nbsp;mIdenDisk( 
        void ) {&nbsp;&nbsp;&nbsp;&nbsp;/* 识别分析当前逻辑盘 
        */<BR>&nbsp;&nbsp;UINT8&nbsp;&nbsp;Status;<BR>&nbsp;&nbsp;DiskStart = 
        0;&nbsp;&nbsp;/* 以下是非常简单的FAT文件系统的分析,正式应用绝对不应该如此简<BR>单 
        */<BR>&nbsp;&nbsp;Status = mReadSector( 0, 1, DISK_BUFFER 
        );&nbsp;&nbsp;/* 读取逻辑盘引导信息 */<BR>&nbsp;&nbsp;if ( Status != 0 ) return( 
        Status );<BR>&nbsp;&nbsp;if ( DISK_BUFFER[0] != 0xEB &amp;&amp; 
        DISK_BUFFER[0] != 0xE9 ) {&nbsp;&nbsp;/* 不是逻辑引导扇<BR>区 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;DiskStart = DISK_BUFFER[0x1C6] | 
        (UINT16)DISK_BUFFER[0x1C7] &lt;&lt; 
        8<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;| 
        (UINT32)DISK_BUFFER[0x1C8] &lt;&lt; 16 | (UINT32)DISK_BUFFER[0x1C9] 
        &lt;&lt; 24;<BR>&nbsp;&nbsp;&nbsp;&nbsp;Status = mReadSector( DiskStart, 
        1, DISK_BUFFER );<BR>&nbsp;&nbsp;&nbsp;&nbsp;if ( Status != 0 ) return( 
        Status );<BR>&nbsp;&nbsp;}<BR>&nbsp;&nbsp;SecPerClus = 
        DISK_BUFFER[0x0D];&nbsp;&nbsp;/* 每簇扇区数 */<BR>&nbsp;&nbsp;RsvdSecCnt = 
        DISK_BUFFER[0x0E];&nbsp;&nbsp;/* 逻辑盘的保留扇区数 */<BR>&nbsp;&nbsp;FATSz16 = 
        mGetPointWord( &amp;DISK_BUFFER[0x16] );&nbsp;&nbsp;/* FAT表占用扇区数 
        */<BR>&nbsp;&nbsp;return( 0 );&nbsp;&nbsp;/* 成功 
        */<BR>}<BR><BR>UINT16&nbsp;&nbsp;mLinkCluster( UINT16 iCluster ) 
        {&nbsp;&nbsp;/* 获得指定簇号的链接簇 */<BR>/* 输入: iCluster 当前簇号, 返回: 原链接簇号, 
        如果为0则说明错误 
        */<BR>&nbsp;&nbsp;UINT8&nbsp;&nbsp;Status;<BR>&nbsp;&nbsp;Status = 
        mReadSector( DiskStart + RsvdSecCnt + iCluster / 256, 1, <BR>DISK_BUFFER 
        );<BR>&nbsp;&nbsp;if ( Status != 0 ) return( 0 );&nbsp;&nbsp;/* 错误 
        */<BR>&nbsp;&nbsp;return( mGetPointWord( &amp;DISK_BUFFER[ ( iCluster + 
        iCluster ) &amp; 0x01FF ] ) 
        );<BR>}<BR><BR>UINT32&nbsp;&nbsp;mClusterToLba( UINT16 iCluster ) 
        {&nbsp;&nbsp;/* 将簇号转换为绝对LBA扇区地址 */<BR>&nbsp;&nbsp;return( DiskStart + 
        RsvdSecCnt + FATSz16 * 2 + 32 + ( iCluster - 2 ) * <BR>SecPerClus 
        );<BR>}<BR><BR>void&nbsp;&nbsp;mInitSTDIO( void ) {&nbsp;&nbsp;/* 
        仅用于调试用途及显示内容到PC机,与该程序功能完全无<BR>关 */<BR>&nbsp;&nbsp;SCON = 0x50; PCON = 
        0x80; TMOD = 0x20; TH1 = 0xf3; TR1=1; TI=1;&nbsp;&nbsp;/* 24MHz, 
        <BR>9600bps */<BR>}<BR>void&nbsp;&nbsp;mStopIfError( UINT8 iErrCode ) 
        {&nbsp;&nbsp;/* 如果错误则停止运行并显示错误状态 */<BR>&nbsp;&nbsp;if ( iErrCode == 0 ) 
        return;<BR>&nbsp;&nbsp;printf( "Error status, %02X\n", (UINT16)iErrCode 
        );<BR>}<BR><BR>main( ) 
        {<BR>&nbsp;&nbsp;UINT8&nbsp;&nbsp;Status;<BR>&nbsp;&nbsp;UINT8X&nbsp;&nbsp;*CurrentDir;<BR>&nbsp;&nbsp;UINT16&nbsp;&nbsp;Cluster;<BR>&nbsp;&nbsp;mDelaymS( 
        200 );&nbsp;&nbsp;/* 延时200毫秒 */<BR>&nbsp;&nbsp;mInitSTDIO( 
        );<BR>&nbsp;&nbsp;CH375_WR_CMD_PORT( CMD_SET_USB_MODE );&nbsp;&nbsp;/* 
        初始化CH375,设置USB工作模式 */<BR>&nbsp;&nbsp;CH375_WR_DAT_PORT( 6 
        );&nbsp;&nbsp;/* 模式代码,自动检测USB设备连接 */<BR>&nbsp;&nbsp;while ( 1 ) 
        {<BR>&nbsp;&nbsp;&nbsp;&nbsp;printf( "Insert USB disk\n" 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;while ( mWaitInterrupt( ) != 
        USB_INT_CONNECT );&nbsp;&nbsp;/* 等待U盘连接 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;mDelaymS( 250 );&nbsp;&nbsp;/* 
        延时等待U盘进入正常工作状态 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;Status = mInitDisk( 
        );&nbsp;&nbsp;/* 初始化U盘,实际是识别U盘的类型,必须进行此步骤 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;mStopIfError( Status 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;Status = mIdenDisk( );&nbsp;&nbsp;/* 
        识别分析U盘文件系统,必要操作 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;mStopIfError( Status 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;Status = mReadSector( DiskStart + 
        RsvdSecCnt + FATSz16 * 2, 32, <BR>DISK_BUFFER 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;mStopIfError( Status );&nbsp;&nbsp;/* 
        读取FAT16逻辑盘的根目录,通常根目录占用32个扇区 <BR>*/<BR>&nbsp;&nbsp;&nbsp;&nbsp;for ( 
        CurrentDir = DISK_BUFFER; CurrentDir[0] != 0; CurrentDir += 32 ) 
        {<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if ( ( CurrentDir[0x0B] &amp; 
        0x08 ) == 0 &amp;&amp; CurrentDir[0] != 0xE5 ) 
        {<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CurrentDir[0x0B] = 
        0;&nbsp;&nbsp;/* 为了便于显示,设置文件名或者目录名的结束标志 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;printf( "Name: 
        %s\n", CurrentDir );&nbsp;&nbsp;/* 通过串口输出显示 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;}&nbsp;&nbsp;/* 
        以上显示根目录下的所有文件名,以下打开第一个文件,如果是C文件的话 */<BR>&nbsp;&nbsp;&nbsp;&nbsp;if ( 
        (DISK_BUFFER[0x0B]&amp;0x08)==0 &amp;&amp; DISK_BUFFER[0]!=0xE5 
        &amp;&amp; DISK_BUFFER[8]<BR>=='C' ) 
        {<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Cluster = mGetPointWord( 
        &amp;DISK_BUFFER[0x1A] );&nbsp;&nbsp;/* 文件的首簇 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;while ( Cluster &lt; 0xFFF8 ) 
        {&nbsp;&nbsp;/* 文件簇未结束 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if ( Cluster == 0 
        ) mStopIfError( 0x8F );&nbsp;&nbsp;/* 对于首簇,可能是0长度文件 
        <BR>*/<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Status = 
        mReadSector( mClusterToLba( Cluster ), SecPerClus, <BR>DISK_BUFFER 
        );<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;mStopIfError( 
        Status );&nbsp;&nbsp;/* 读取首簇到缓冲区 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;DISK_BUFFER[30] = 
        0; printf( "Data: %s\n", DISK_BUFFER );&nbsp;&nbsp;/* 显示首行 
        <BR>*/<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Cluster = 
        mLinkCluster( Cluster );&nbsp;&nbsp;/* 获取链接簇,返回0说明错误 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;while 
        ( mWaitInterrupt( ) != USB_INT_DISCONNECT );&nbsp;&nbsp;/* 等待U盘拔出 
        */<BR>&nbsp;&nbsp;&nbsp;&nbsp;mDelaymS( 250 
        );<BR>&nbsp;&nbsp;}<BR>}<BR><BR><BR><BR>(文章推荐人：丁丁) 
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