Win 8.1 and USB HID

[kberisso]

I was hoping to get some help (and maybe some education) on talking to USB HID devices with the new Win 8.1 System.Devices.HumanInterfaceDevice namespace. I am trying to connect to a device via the "endpoints" instead of via reports... first, what is the difference. I have been looking and can't quite make out what the differences. And more importantly, how do I communicate to the device? I have used your sample code in the past to talk to the device, and am now trying to upgrade the apps to the newer Windows 8.1 Store Apps.

Thanks

Kevin

[Jan Axelson]

The documentation here:

http://msdn.microsoft.com/en-us/library/windows/apps/bg182882.aspx#one

says:

Apps retrieve data from a HID device by using input reports.

and gives this example:

var inputReport = await DeviceList.Current.CurrentDevice.GetInputReportAsync(SuperMutt.ReadWriteBuffer.ReportId);

Can you give an example of what you're attempting?

[kberisso]

Thanks for the quick reply.

I have been to the site and can "see" the USB device (it is an RFID reader that is set up as a USB HID device with the following info:

Device Descriptor:
bcdUSB:             0x0110
bDeviceClass:         0xFF
bDeviceSubClass:      0x00
bDeviceProtocol:      0xFF
bMaxPacketSize0:      0x08 (
bcdDevice:          0x0001
bNumConfigurations:   0x01

ConnectionStatus: DeviceConnected
Current Config Value: 0x01
Device Bus Speed:     Full
Device Address:       0x04
Open Pipes:              2

Endpoint Descriptor:
bEndpointAddress:     0x01  OUT
Transfer Type:   Interrupt
wMaxPacketSize:     0x0040 (64)
bInterval:            0x01

Endpoint Descriptor:
bEndpointAddress:     0x82  IN
Transfer Type:   Interrupt
wMaxPacketSize:     0x0040 (64)
bInterval:            0x01

Configuration Descriptor:
wTotalLength:       0x0029
bNumInterfaces:       0x01
bConfigurationValue:  0x01
iConfiguration:       0x00
bmAttributes:         0xC0 (Bus Powered Self Powered )
MaxPower:             0xFA (500 Ma)

Interface Descriptor:
bInterfaceNumber:     0x00
bAlternateSetting:    0x00
bNumEndpoints:        0x02
bInterfaceClass:      0x03 (HID)
bInterfaceSubClass:   0x00
bInterfaceProtocol:   0x00
iInterface:           0x00

HID Descriptor:
bcdHID:             0x0111
bCountryCode:         0x00
bNumDescriptors:      0x01
bDescriptorType:      0x22
wDescriptorLength:  0x0062

Endpoint Descriptor:
bEndpointAddress:     0x01  OUT
Transfer Type:   Interrupt
wMaxPacketSize:     0x0040 (64)
bInterval:            0x01

Endpoint Descriptor:
bEndpointAddress:     0x82  IN
Transfer Type:   Interrupt
wMaxPacketSize:     0x0040 (64)
bInterval:            0x01

I am trying to send it a command (4349544DFF130000000000000000) that is 16 bytes long.

What I don't get (and never really understood even with the WinXP/7 version of my program) is how the endpoints relate to the reports. I am assuming that the "In" endpoint is the input report and the "Out" endpoint is the output report, but if that is the case, I can't seem to get my command string into the report

I tried:

                    var output = myDevice.CreateOutputReport();
                    var dataWriter = new DataWriter();
                    dataWriter.WriteBytes(myData);
                    dataWriter.DetachBuffer();

                    uint result = await myDevice.SendOutputReportAsync(output);

but always get a Access Denied error when I hit the last line (where I send the report). I know that I have a good device and have confirmed that myDevice is valid (or at least I can see a VID/PID and other related info).

Thanks

Kevin