edf8e16c_NC_USB_HID_interface_component__Description
[USB Data Type] Input Value > 1 Bit, usage=HATSWITCH [Common Usage] Hat switch [Description] 
The hat switch is a special case of an input value. The devices sets the control's recommended usage to HATSWITCH. The data is then interpreted as a directional key press. If the key isn't pressed, an out of range value is returned.
hidcomp - EMC/LinuxCNC USB HID interface component
Description