Raw volume access to SD Card (USB adapter)

Hello,

I'm new in this Forum and has following Issue:
I need to read and write to an sd Card at raw level (without FAT). I read and write Data Sectorwise (512Bytes) with a µC to the SD Card. This Data I need on the PC. It's a SD card in a card reader. There are API Funktions to do that, but I never used API Funktions. I found an old Thread in this Forum: http://cboard.cprogramming.com/windo...sb-volume.html
Has anybody solved this?

Thanks!

CreateFile Function (Windows)

Read the section on Physical Disks and Volumes.

Thanks for the reply!

I use followinf funktion:

Code:

---

void tmain(void)
{
    HANDLE hFile;
    DWORD dwBytesRead = 0;
    char ReadBuffer[BUFFER_SIZE] = {0};

        hFile = CreateFile("\\.\E:",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);


    if (hFile == INVALID_HANDLE_VALUE)
    {
        printf("Could not open file (error %d)\n", GetLastError());
        return;
    }

    // Read one character less than the buffer size to save room for
    // the terminating NULL character.

    if( FALSE == ReadFile(hFile, ReadBuffer, BUFFER_SIZE-2, &dwBytesRead, NULL) )
    {
        printf("Could not read from file (error %d)\n", GetLastError());
        CloseHandle(hFile);
        return;
    }

    if (dwBytesRead > 0)
    {
        ReadBuffer[dwBytesRead+1]='\0'; // NULL character

        _tprintf(TEXT("Text read from %s (%d bytes): \n"), dwBytesRead);
        printf("%s\n", ReadBuffer);
    }
    else
    {
        _tprintf(TEXT("No data read from file %s\n"));
    }

    CloseHandle(hFile);
}

---

But it always jumps into this Funktion

Code:

---

if (hFile == INVALID_HANDLE_VALUE)

---

because of hFile is 0xffffffff

What can I do?

Does nowbody have an idea?
Now I use following parameters for this function:

Code:

---

hFile = CreateFile("\\.\E:",GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ,NULL,OPEN_EXISTING,FILE_FLAG_NO_BUFFERING,NULL);

---

But I'm not able to open the volume??

remember that visual studio views characters preceded by a \ as a switch. The proper text is

Code:

---

hFile = CreateFile("\\\\.\\E:",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);

---

Thanks a lot!!
It worked!

Hello,

I have one more question to this issue.
Following code example works fine to read all data from the SD-Card. Each reading goes one sector forward. But how can I read from different sectors, for example sector 34?

Code:

---

        private: System::Void button3_Click(System::Object^  sender, System::EventArgs^  e) {
                                if( FALSE == ReadFile(hFile, ReadBuffer, BUFFER_SIZE, &dwBytesRead, NULL) )
                                {
                                        CloseHandle(hFile);
                                        return;
                                }

                                if (dwBytesRead > 0)
                                {

                                        String ^ str = gcnew String(ReadBuffer);
                                        textBox1->AppendText(str);

                                        while(ReadBuffer[2] != 0x00) // reads until the end
                                        {
                                                ReadFile(hFile, ReadBuffer, BUFFER_SIZE, &dwBytesRead, NULL);
                                                String ^ str = gcnew String(ReadBuffer);
                                                textBox1->AppendText(str);
                                        }
                                }
                                else
                                {
                                        MessageBox::Show("No data read from volume");
                                }
                }

---

Hello,
I figured it out how to read sectorwise, with the SetFilePointer API.
Now my last problem is, how can I read out the filesystem?
I tried it with the API GetVolumeInformation, but it only works on c: or my CDROM drive, but not with the SD-Card?
My goal is, to get back the filesystemname "RAW" from the SD-Card like the information from the properties of windows.