usb_hid_device Directory Reference

Directory dependency graph for usb_hid_device:

Directories
	src

Detailed Description

USBX HID device demo. The board enumerates on USB-FS as a three-button boot-protocol mouse – the canonical descriptor from USB HID 1.11 sec E.10 – and pushes a four-pixel cursor jiggle to the host once a second on the interrupt-IN pipe, with LED1 toggling per report sent.

It is manual because the proof is on the host: the pointer has to actually move, which only happens once the host's HID driver has bound and opened the device.

VBUSEN must be a GPIO driven low

Routing VBUSEN to its peripheral function forces the pin high, which is host mode, and blocks device enumeration outright. The app configures it as a GPIO output at low instead.

Multi-packet EP0 IN is where this class breaks

The HID report descriptor is larger than one control packet, so the host fetches it in several EP0 IN chunks, and EP0 is single-buffered: after a chunk is pushed, FRDY does not reassert until the host has actually pulled it. The wait therefore has to observe the clear-then-reassert transition, and its bound has to cover host latency. Get that wrong and the symptom is a clean chapter-9 enumeration followed by the host timing out on the descriptor fetch – usbhid reports -110 – which looks nothing like a FIFO problem.

g_usb_hid_match and g_usb_hid_mismatch are readable over SWD. They only advance once the host has opened the HID device, which cannot happen until the report-descriptor handshake completes, so they double as a pass indicator on a run with no screen attached.