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HID Controls

Some controls don't go through DCS-BIOS — flight-control axes, and momentary controls with no DCS-BIOS address. These take the HID path: they appear to the PC as a standard USB joystick, handled entirely by SimGateway. PanelBridge never sees them. This page is the controlId reference for that path. For when to use HID vs DCS-BIOS, see DCS-BIOS vs HID.

controlId ranges

HID controls use controlId values below 0x8000, allocated in HIDControls.h:

Range Type Handler USB capacity
0x0010–0x001F Axes HIDAxis 8 axes
0x0020–0x002F Hat switches HIDHatSwitch 4 hats
0x0030–0x00AF Buttons HIDButton 128 buttons
0x00B0–0x00FF Reserved HID expansion — not exposed

CTRL_ID_HID_MIN = 0x0010, CTRL_ID_HID_MAX = 0x00FF.

The CTRL_* constants

From Firmware/Libraries/HIDControls/HIDControls.h — the authoritative source:

Constant Value Control
CTRL_ROLL 0x0010 Roll axis — stick sub-node
CTRL_PITCH 0x0011 Pitch axis — stick sub-node
CTRL_THROTTLE 0x0012 Throttle lever — throttle sub-node
CTRL_RUDDER 0x0013 Rudder axis — pedal sub-node
CTRL_BRAKE_L 0x0014 Left toe brake — pedal sub-node
CTRL_BRAKE_R 0x0015 Right toe brake — pedal sub-node
CTRL_ZOOM 0x0016 Zoom axis
CTRL_HAT_0 0x0020 Hat switch 0 — stick grip
CTRL_TRIGGER 0x0030 Trigger — button index 0

That's 7 of the 8 available axes — the planned out-of-console HOTAS allocation (stick, rudder pedals, replica throttle). The throttle panel is a separate Left Console DCS-BIOS panel; only the throttle axis is HID. The speed brake is a DCS-BIOS switch, not an axis.

How HID controls are declared

Unlike DCS-BIOS controls (which need no sketch declaration — the input map covers them), HID controls are declared on the SimGateway sketch, binding a controlId to a joystick slot:

OpenSkyhawk::HIDAxis   roll   (CTRL_ROLL,    0);  // axis index 0
OpenSkyhawk::HIDAxis   throttle(CTRL_THROTTLE, 2);
OpenSkyhawk::HIDButton trigger(CTRL_TRIGGER,  0);  // button index 0
OpenSkyhawk::HIDHatSwitch hat (CTRL_HAT_0,    0);  // hat index 0

The matching PanelGroup input fires the same controlId; SimGateway maps it to the joystick report:

  • HIDAxis — incoming 0–65535 mapped to ±32767 (value − 32768)
  • HIDButton — value != 0 → pressed
  • HIDHatSwitch — direction nibble (0 = centered, 1–8 = N…NW)

After draining all HID frames in a loop, SimGateway calls OsJoystick.send() once. The USB HID profile is 8 axes / 128 buttons / 4 hats — see SimGateway for the descriptor and platform limits.