請問各位: USB是要如何做,才能讀寫? RS232是利用createfile(),writefile(),readfile()來進行,,, 那USB是如可用呢? 望有範例解說.

Hi~kenbcb 參考這篇對岸的範例吧~ http://www.cppfans.com/articles/system/bcb_usb_a.asp

參考一下    【分享】偵測USB裝置插入哪一個USB Port插槽  http://delphi.ktop.com.tw/topic.php?TOPIC_ID=59211

kenbcb 您好 之前有研究過USB，你若要對USB做讀寫動作，要先了解File System喔，而且還包括有FAT12,FAT16,FAT32的區別喔，相信你搜尋一下站內資源應該會找到相關的，在假設你也了解FAT，若只是要做讀和寫動作 我是這樣做，會用到這些function： 先要取得device的handle  

 
HANDLE DISC_device_select(char deviceNo)
{
    ULONG accessMode = 0, shareMode = 0;
    ULONG length = 0,
    errorCode = 0,
    returned = 0,
    sectorSize = 512;
    UCHAR string[25];
    sprintf((char *)(string),"\\\\.\\%c:",deviceNo);
    shareMode  = FILE_SHARE_READ | FILE_SHARE_WRITE;  // default
    accessMode = GENERIC_WRITE | GENERIC_READ;       // default
    sectorSize = 512;        fileFATHandle = CreateFile( (char *)  string,accessMode,shareMode,NULL,OPEN_EXISTING,0,NULL);        if (fileFATHandle == INVALID_HANDLE_VALUE) 
        {
                printf("Error opening %s. Error: %d\n",
                        string, errorCode = GetLastError());
                //        PrintError(errorCode);
                return NULL;
        }
        return fileFATHandle;
}

接下來就是將USB裡的data讀進來

void HD_read_sector_lba(UCHAR *tmpbuff,int Lba,int nBlock)
{
 memset(tmpbuff,0,2048*nBlock);
 int addr;
 addr = Lba*512;
 FindBuffLen = nBlock*512;
 setfilepointer(addr);
 ReadFile(
                        fileFATHandle,                // handle to file           
                        tmpbuff,                      // data buffer
                        FindBuffLen,                  // number of bytes to read
                        &nNumberOfBytesRead,          // number of bytes read
                        NULL // lpOverlapped          // overlapped buffer
                        );
 
}
//-----------------------------------------------------------------
void setfilepointer(ULONG address)
{
 SetFilePointer
 (
                fileFATHandle,     // handle to file
                address,       // bytes to move pointer
                NULL,                        // bytes to move pointer
                FILE_BEGIN      // starting point
 );
}
 

至於寫的動作

void FATWriteBuff(int address,UCHAR *tmpbuff,int length)
{
  DWORD dwPos;
  dwPos = SetFilePointer(fileFATHandle,address,NULL,FILE_BEGIN);
  LockFile(fileFATHandle,dwPos,0,dwPos nNumberOfBytesRead,0);
  WriteFile(
           fileFATHandle,                // handle tofile           
           tmpbuff,                      // data buffer
           length,                      // number of bytes to read
           &nNumberOfBytesRead,          // number of bytes read
           NULL  // lpOverlapped         // overlapped buffer
          );
  UnlockFile(fileFATHandle,dwPos,0,dwPos nNumberOfBytesRead,0);
}
 

這裡我只要表達如何使用createfile(),writefile(),readfile() 至於USB要如何用，你要說明是應用在何處，才能幫你阿