MSP430f550x Keyboard HID

> I found this useful document that discusses this process on another MCU.

Thanks, I'm glad to hear my post is useful for you.

> The one thing I did notice is that on the MSP430 Mouse example the bDeviceProtocol is actually set to 0 (None) where it should be 2 for Mouse and 1 for keyboard.

Ah, I didn't write on this issue on above post.

Maybe you refer to the triad (bInterfaceClass / bInterfaceSubclass / bInterfaceProtocol), on the interface descriptor.

bInterfaceSubclass / bInterfaceProtocol fields are seen only by BIOS, just after PC powers up. BIOS recognizes a HID device as mouse or keyboard according to these fields.

When OS runs after BIOS, these fields are ignored. HID class driver on the OS reads out the report descriptor on the device. The USAGE of the Top-Level Collection on the report descriptor determines the type of the HID device.

> Working my way through it I have updated all the descriptors, and report formats, but so far have not been able to get Keyboard working.

Delete old device instance(s) on Windows, whenever you change any descriptor of your device. OR, assign a new VID/PID (at least new PID) to the device.

Windows hold device instance(s) on the registry for each USB device, which keep the information of descriptors. Device instance is indexed with VID/PID. Device instance is made at the first plug-in of the device, and it isn't updated when you change the descriptors. Therefore, modification of descriptors on the device causes conflict with the registry.

To delete device instance, USBDeview is helpful
http://www.nirsoft.net/utils/usb_devices_view.html

- Plug-off your device, first. USBDeview lists up all registered USB devices, even without the device plug in.
- Sort the list on USBDeview by Vendor ID (VID). For HID device, you may find two instances of the VID/PID of your device.
- Delete (uninstall) all of them, by right click on the line.
- Plug-in your device, and Windows make new device instance, which reflects updated descriptors.

Of course, there are many pitfalls in USB device implementation.
But try this one, first.

Tsuneo

Hi Tsuneo,

Nice to see you here!  Thanks for you reply, and the info wrt Silabs example.
Good tip re USBDeview.  I was looking for something like this!  I can confirm that the VID/PID is new on my device.

The problem is actually more fundamental, as I am ney even getting enumeration.  On windows I get a " ! USB Device Not Recognised" error when plugging in the device with the new keyboard descriptors.  It enumerates ok on Linux, although I get no keyboard data through the pipe.  I think Windows is much stricted on having sensible descriptors so I think the problem must be in there somewhere, but I just can't seem to locate it.

The mouse example uses 2 endpoints, presumebly 1 for movement and the other for feedback to LED's (if any).   So I would presume that the keyboard also uses two endpoints (1x IN and 1x OUT), again with the OUT for LED's.  I notice that in you Silabs posts you advise to delete the OUT endpoint.  Can I leave this in, and how does it change the descriptors...  I have listed my descriptors below, can you see anything wrong?  I have left out the string descriptors as I'm pretty sure they are good.

In particular I have changed wTotalLength... I changed it to 59 as it was 41 for mouse.
Also my report array is now 8byts rather than 4 for mouse....

Thanks for any help!!!

Rob.

/*-----------------------------------------------------------------------------+
| Device Descriptor |
|-----------------------------------------------------------------------------*/

const

abromDeviceDescriptor[SIZEOF_DEVICE_DESCRIPTOR] = {
  SIZEOF_DEVICE_DESCRIPTOR,    // 0x12 Length of this descriptor
  DESC_TYPE_DEVICE,            // 0x01 Type code of this descriptor
  0x00, 0x02,                  //      Release of USB spec
  0x00,                        //      Device's base class code
  0x00,                        //      Device's sub class code
  0x00,                        //      Device's protocol type code
  EP0_PACKET_SIZE,             // 0x08 End point 0's packet size
  USB_VID&0xFF, USB_VID>>8,    // 0x0471 Vendor ID for device, TI=0x2047
  USB_PID&0xFF, USB_PID>>8,    // 0x0206 Product ID for device,
  VER_FW_L, VER_FW_H,          // 0x00, 0x02 Revision level of device
  1,                           // Index of manufacturer name string desc
  2,                           // Index of product name string desc
  USB_STR_INDEX_SERNUM,        // 0x03 Index of serial number string desc
  1                            // Number of configurations supported
};

      /* end of HID[0]*/
    }
  },
/******************************************************* end of HID**************************************/
};

BYTE

const abromReportDescriptor[SIZEOF_REPORT_DESCRIPTOR]= // For KEYBOARD
{
  0x05, 0x01, // Usage Pg (Generic Desktop)
  0x09, 0x06, // Usage (Keyboard)
  0xA1, 0x01, // Collection: (Application)
  0x05, 0x07, // Usage Page (Key Codes)
  0x19, 0xE0, // Usage Minimum (224)
  0x29, 0xE7, // Usage Maximum (231)
  0x15, 0x00, // Logical Minimum (0)
  0x25, 0x01, // Logical Maximum (1)
  0x75, 0x01, // Report Size (1)
  0x95, 0x08, // Report Count (8)
  0x81, 0x02, // Input (Data, Variable, Absolute) ;Modifier byte
  0x95, 0x01, // Report Count (1)
  0x75, 0x08, // Report Size (8)
  0x81, 0x01, // Input (Constant) ;Reserved byte
  0x95, 0x05, // Report Count (5)
  0x75, 0x01, // Resport Size (1)
  0x05, 0x08, // Usage Page (Page# for LEDs)
  0x19, 0x01, // Usage Minimum (1)
  0x29, 0x05, // Usage Maximum (5)
  0x91, 0x02, // Output (Data, Variable, Absolute) ;LED report
  0x95, 0x01, // Report Count (1)
  0x75, 0x03, // Report Size (3)
  0x91, 0x01, // Output (Constant) ;LED report padding
  0x95, 0x06, // Report Count (6)
  0x75, 0x08, // Report Size (8)
  0x15, 0x00, // Logical Minimum (0)
  0x25, 0x65, // Logical Maximum (101)
  0x05, 0x07, // Usage Page (Key Codes)
  0x19, 0x00, // Usage Minimum (0)
  0x29, 0x65, // Usage Maximum (101)
  0x81, 0x00, // Input (Data, Array) ;Key arrays (6 bytes)
  0xC0 // End Collection
};

Quick update...

I change wTotalLength back to 41, and now the device enumerates...  It's clear I don't understand the point of wTotalLenght.
However I still do not get any keyboard events.  So please if anyone can take a look at my descriptors aboave and confirm that this should be good for a HID Keyboard?

Many thanks!
Rob.

Hi Rob,

1) wTotalLength is no of bytes of configuration descriptor.

2) In interface descriptor we should give information of bInterfaceprotocol and bInterfaceSubClass.

bInterfaceSubClass:  1 // 1- for boot interface 0- Report interface

bInterfaceProtocol: 1 // 1: for keyboard

3) In Endpoint descriptors, wMaxPacketSize value  need to change to 8 bytes for Keyboard transaction.

With these changes try once. Hope it will work. 

Regards

SuryaG

Surya Narayana said:

1) wTotalLength is no of bytes of configuration descriptor.  

Yep figured that out.  Thanks!

Surya Narayana said:

 2) In interface descriptor we should give information of bInterfaceprotocol and bInterfaceSubClass.

bInterfaceSubClass:  1 // 1- for boot interface 0- Report interface

bInterfaceProtocol: 1 // 1: for keyboard  

Thanks.  I don't need boot mode, so as Tsueno mentioned the keyboard can be identified by the report descriptor, but I will try this on Monday and see if it helps.

Surya Narayana said:

 3) In Endpoint descriptors, wMaxPacketSize value  need to change to 8 bytes for Keyboard transaction.

I was wondering about this.  The 64 was set in the Mouse example, but the Mouse transaction is only 4 bytes.!  Then I saw in the TI MSP430 USB API document that the API has a fixed transaction size of 64, so I just left it.  Although in the code I am only sending 8 bytes to sendReport().

A little confusing.  Does anyone else know anymore about this?

I'm playing around in the code at the moment, but debugging is tough as it's hard to see if any data is actually going across the bus.

Are there any host side tools that can "sniff" the USB to look at the report data.

Thanks again for all you continued help.

Rob.