Certainly! HID descriptors can be a bit complex, but here’s a breakdown of common Usage Pages and Usages, along with their options. This will help when designing HID devices like gamepads, joysticks, keyboards, and more.
- Usage Pages group related Usages (specific controls) together.
- Usage Pages are defined by a 16-bit identifier.
| Usage Page Name | ID (Hex) | Description |
|---|---|---|
| Generic Desktop Controls | 0x01 |
Basic controls like joysticks, mice, keyboards, etc. |
| Simulation Controls | 0x02 |
Controls for simulation devices, such as flight controls and vehicles. |
| VR Controls | 0x03 |
Virtual reality devices and controls. |
| Sports Controls | 0x04 |
Controls for sports equipment and games. |
| Game Controls | 0x05 |
Controls for gamepads and gaming devices. |
| Keyboard/Keypad | 0x07 |
Standard keyboard keys and related inputs. |
| LEDS | 0x08 |
LED indicators, often used in keyboards (e.g., Caps Lock, Num Lock). |
| Button | 0x09 |
Generic buttons (used by gamepads, mice, etc.). |
| Consumer | 0x0C |
Consumer devices (like volume controls, media buttons). |
| Digitizer | 0x0D |
Controls for digitizers, touch screens, and stylus devices. |
| Alphanumeric Display | 0x14 |
Controls for alphanumeric displays. |
- Usages define specific controls within a Usage Page.
- Each Usage has an associated ID within its Usage Page.
| Usage | ID (Hex) | Description |
|---|---|---|
| Pointer | 0x01 |
General pointer device, often a mouse. |
| Mouse | 0x02 |
Mouse device. |
| Joystick | 0x04 |
Joystick controller. |
| Gamepad | 0x05 |
Gamepad or controller. |
| Keyboard | 0x06 |
Keyboard device. |
| X | 0x30 |
X-axis of a joystick or mouse. |
| Y | 0x31 |
Y-axis of a joystick or mouse. |
| Z | 0x32 |
Z-axis (forward/backward) |
| Rx | 0x33 |
Rotation around X-axis (tilt) |
| Ry | 0x34 |
Rotation around Y-axis (turning) |
| Rz | 0x35 |
Rotation around Z-axis (twisting) |
| Slider | 0x36 |
Linear movement (e.g., throttle). |
| Dial | 0x37 |
Rotation for dials (continuous). |
| Wheel | 0x38 |
Wheel rotation (e.g., steering wheel). |
| Hat switch | 0x39 |
Directional hat switch |
- This Usage Page is straightforward and represents individual button presses, typically used for game controllers, mice, and other devices with buttons.
- Each button has an ID like
0x01,0x02, etc., up to the number of buttons needed.
- This Usage Page includes controls for media and consumer electronics.
| Usage | ID (Hex) | Description |
|---|---|---|
| Volume Up | 0xE9 |
Increase volume |
| Volume Down | 0xEA |
Decrease volume |
| Mute | 0xE2 |
Mute audio |
| Play/Pause | 0xCD |
Play/pause toggle |
| Stop | 0xB7 |
Stop playback |
| Next Track | 0xB5 |
Skip to the next track |
| Previous Track | 0xB6 |
Go to the previous track |
| Usage | ID (Hex) | Description |
|---|---|---|
| Flight Control Stick | 0x20 |
Basic flight control stick. |
| Auto-Pilot Enable | 0x44 |
Auto-pilot toggle. |
| Throttle | 0xBB |
Throttle control. |
Here’s how you might define some of these usages in your descriptor:
-
Gamepad with X, Y, Z Axes:
0x05, 0x01, // Usage Page (Generic Desktop) 0x09, 0x04, // Usage (Joystick) 0xA1, 0x01, // Collection (Application) 0x15, 0x81, // Logical Minimum (-127) 0x25, 0x7F, // Logical Maximum (127) 0x75, 0x08, // Report Size (8 bits) 0x95, 0x03, // Report Count (3) 0x09, 0x30, // Usage (X) 0x09, 0x31, // Usage (Y) 0x09, 0x32, // Usage (Z) 0x81, 0x02, // Input (Data, Variable, Absolute) 0xC0 // End Collection
-
Gamepad with Rx, Ry, Rz Axes for Rotation:
0x05, 0x01, // Usage Page (Generic Desktop) 0x09, 0x05, // Usage (Gamepad) 0xA1, 0x01, // Collection (Application) 0x15, 0x81, // Logical Minimum (-127) 0x25, 0x7F, // Logical Maximum (127) 0x75, 0x08, // Report Size (8 bits) 0x95, 0x03, // Report Count (3) 0x09, 0x33, // Usage (Rx) 0x09, 0x34, // Usage (Ry) 0x09, 0x35, // Usage (Rz) 0x81, 0x02, // Input (Data, Variable, Absolute) 0xC0 // End Collection
These descriptors should give you a lot of flexibility in defining a wide variety of controls. Let me know if you need help with specific configurations!