how to add output report capability to HID device

Please see the following forum posts that address this question:
http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/p/295357/1031180.aspx#1031180 http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/247645.aspx http://e2e.ti.com/support/microcontrollers/tiva_arm/f/908/t/297332.aspx

Section 2.13.4 of the USB Library user's guide talks about handling HID reports:
http://www.ti.com/litv/pdf/spmu297

Hi Yanil,

It is briefly described on "TivaWare USB Library"
http://software-dl.ti.com/tiva-c/SW-TM4C/latest/exports/SW-TM4C-USBL-UG-2.0.1.11577.pdf
at the end of "2.13.4 Handling HID Reports" section, starting with this paragraph,
(P85) Output and Feature reports are sent from the host to the device to instruct it to set various parameters and options. ..

But just with this brief explanation, it's too hard to implement Output/Feature report, without enough USB background.

For the Output report over the interrupt OUT endpoint, you may refer to the HID keyboard example, which lights LEDs using Output report.
C:\ti\TivaWare_C_Series-2.0.1.11577\usblib\device\usbdhidkeyb.c

The output report is defined in the report descriptor ( g_pui8KeybReportDescriptor[] ).
When an output report comes, HIDKeyboardRxHandler() is called with the packet.

Unfortunately, there is no example of Output/Feature report over the defualt endpoint.
But the stack is well designed to support this method.
With a little modification, you'll implement it.

How many bytes, and how often do you send the "output" from PC to the device?
When the "output" is large and often, interrupt OUT endpoint is better than the default endpoint.


Anyway, the library document has a minor mistake,
(p85) If using a dedicated endpoint for output and feature reports,

Feature report isn't sent over the interrupt OUT endpoint.
Just Output report is.

Tsuneo