Talking to USB devices

Hi All!

I try to communicate with USB devices. I successfully get a device path for calling CreateFile() to communicate with USB device. But I have trouble with calling ReadFile() and WriteFile(). The calling of these functions always end with 5 code error.

I don't understand what I do wrong. Maybe the drivers of my devices just don't allow to communicate with device or I made a mistake in my code.

Please help.

There is my programming code:

Code:

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void _tmain(int argc, _TCHAR* argv[])
{
        //GUID hidGuid = CLSID_NULL; // Disk Device.
        //CLSIDFromString(L"{53f56307-b6bf-11d0-94f2-00a0c91efb8b}", &hidGuid);

        GUID hidGuid = CLSID_NULL; // Human Interface Device (HID).
        HidD_GetHidGuid(&hidGuid);

        //GUID hidGuid = CLSID_NULL; // USB Device.
        //CLSIDFromString(L"{36FC9E60-C465-11CF-8056-444553540000}", &hidGuid);

        //GUID hidGuid = CLSID_NULL; // USB Raw Device.
        //CLSIDFromString(L"{A5DCBF10-6530-11D2-901F-00C04FB951ED}", &hidGuid);

        HDEVINFO devInfo = SetupDiGetClassDevs(&hidGuid, NULL, NULL, DIGCF_DEVICEINTERFACE | DIGCF_PRESENT);

        SP_DEVINFO_DATA devInfoData;
        devInfoData.cbSize = sizeof(SP_DEVINFO_DATA);

        for(int i = 0; SetupDiEnumDeviceInfo(devInfo, i, &devInfoData); i++)
        {
                //printf("Iteration Number: %d\n", i);
                //ShowDeviceProperty(devInfo, devInfoData);

                SP_DEVICE_INTERFACE_DATA devInterfaceData;
                devInterfaceData.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);

                for(int j = 0; SetupDiEnumDeviceInterfaces(devInfo, &devInfoData, &hidGuid, j, &devInterfaceData); j++)
                {
                        DWORD bufferSize = 0;
                        SetupDiGetDeviceInterfaceDetail(devInfo, &devInterfaceData, NULL, 0, &bufferSize, &devInfoData);

                        PSP_DEVICE_INTERFACE_DETAIL_DATA pDeviceInterfaceDetailData = (PSP_DEVICE_INTERFACE_DETAIL_DATA)malloc(bufferSize);
                        pDeviceInterfaceDetailData->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
                       
                        SetupDiGetDeviceInterfaceDetail(devInfo, &devInterfaceData, pDeviceInterfaceDetailData, bufferSize, &bufferSize, &devInfoData);

                        SECURITY_ATTRIBUTES securityAttributes;
                        memset(&securityAttributes, 0, sizeof(SECURITY_ATTRIBUTES));
                        securityAttributes.nLength = sizeof(SECURITY_ATTRIBUTES);
                        securityAttributes.bInheritHandle = true;

                        HANDLE fileHandle = CreateFile(pDeviceInterfaceDetailData->DevicePath, 0, FILE_SHARE_READ|FILE_SHARE_WRITE,
                                &securityAttributes, OPEN_EXISTING, 0, NULL);

                        printf("File handle value %d\n", fileHandle);
                        if ((int)fileHandle != -1)
                        {
                                /*HIDP_CAPS Capabilities;
                                PHIDP_PREPARSED_DATA PreparsedData;
                                HidD_GetPreparsedData(fileHandle, &PreparsedData);
                                printf("HidD_GetPreparsedData error: %d\n", GetLastError());
                                HidP_GetCaps(PreparsedData, &Capabilities);*/
                               

                                HIDD_ATTRIBUTES        attributes;
                                memset(&attributes, 0, sizeof(HIDD_ATTRIBUTES));
                                attributes.Size = sizeof(HIDD_ATTRIBUTES);

                                HidD_GetAttributes(fileHandle, &attributes);
                                printf("Device attribute: %d, %d, %d\n", attributes.ProductID, attributes.VendorID, attributes.VersionNumber);

                                char bufRead[256] = {0};
                                DWORD countRead = 0;
                                if(!ReadFile(fileHandle, bufRead, 5, &countRead, NULL))
                                {
                                        printf("Reading file error %d\n", GetLastError());
                                }
                               
                                char bufWrite[] = {'7', '8', '9', ' '};
                                DWORD countWritten = 0;
                                if(!WriteFile(fileHandle, bufWrite, 3, &countWritten, NULL))
                                {
                                        printf("Writing file error %d\n", GetLastError());
                                }
                        }
                        else
                        {
                                printf("Error code: %d\n", GetLastError());
                        }

                        free(pDeviceInterfaceDetailData);
                }

                printf("____________________\n");
        }

        SetupDiDestroyDeviceInfoList(devInfo);
}

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Thank you much for your consideration.

Please use code tags when posting code: http://www.codeguru.com/forum/misc.php?do=bbcode#code
Once you edit your post and re-copy the code with indentation, folks will be more likely to look at it.

Few things I see:
* Check for errors on all API functions.
* Try using NULL instead of the empty securityAttributes.
* Once you do open a device, you typically call HidD_GetAttributes() first thing to see if it's the ProductId/VenderId of the device you intend to work with.
* Second parameter to CreateFile, dwDesiredAccess, is zero (as it typically for HID devices), so don't expect ReadFile/WriteFile to work. You usually just use Hid functions once you get a handle.

gg

Hey Askold, did you ever get that code to work ?