Files
stickshid/stk/stk.h
T
portersky 8276b7bad5 fix: map throttle to axis 3 (AETR layout)
Verified via hid_discover caps and live data dump. Throttle
responds on axis 3 (HID usage 0x33 = Rx), not axis 5 or 6.
2026-06-14 19:26:37 +02:00

124 lines
3.9 KiB
C

/**
* @file stk.h
* @brief EdgeTX RC library interface for HID joystick mode.
*
* Reads raw HID input reports from the EdgeTX radio and exposes
* 4 analog axes (sticks + throttle) and 24 digital buttons
* (switches, rockers, paddles).
*
* @par Report layout (20 bytes):
* @code
* byte 0 : report ID (0x00)
* byte 1 : buttons bits 0..7
* bytes 2..17 : 8 axes x 16-bit LE (HID usage 0x30..0x37)
* bytes 18..19 : buttons bits 8..23
* @endcode
*
* @par Active axes (AETR stick mapping):
* | Index | Usage | HID name | Physical control | Rest value |
* |-------|-------|----------|-----------------|------------|
* | 0 | 0x30 | X | unused | always 0 |
* | 1 | 0x31 | Y | right stick X | ~1024 |
* | 2 | 0x32 | Z | right stick Y | ~1024 |
* | 3 | 0x33 | Rx | throttle | ~0 |
* | 4 | 0x34 | Ry | left stick X | ~1024 |
* | 5..7 | — | unused | always 0 | always 0 |
*/
#pragma once
#include <stdint.h>
// ---------------------------------------------------------------------------
// Axis range (10-bit ADC on the radio)
// ---------------------------------------------------------------------------
#define STK_AXIS_MIN 0
#define STK_AXIS_MAX 2047
#define STK_AXIS_MID 1024
// ---------------------------------------------------------------------------
// Default device IDs (EdgeTX radio in HID joystick mode)
// ---------------------------------------------------------------------------
#define STK_DEFAULT_VID 0x1209
#define STK_DEFAULT_PID 0x4F54
// ---------------------------------------------------------------------------
// Configuration
// ---------------------------------------------------------------------------
typedef struct {
uint16_t vendor_id;
uint16_t product_id;
} stk_config_t;
// ---------------------------------------------------------------------------
// Radio state
//
// axes[] holds all 8 HID axes (indices 0-7). Only indices 1, 2, 3, 4
// are wired to physical controls (AETR layout). The rest stay at 0.
//
// buttons is a 24-bit bitmask: bit N set = switch/button N+1 pressed.
// ---------------------------------------------------------------------------
#define STK_NUM_AXES 8
#define STK_NUM_BUTTONS 24
typedef struct {
int16_t axes[STK_NUM_AXES];
uint32_t buttons;
} stk_state_t;
// ---------------------------------------------------------------------------
// Convenience accessors for the 4 active axes
// ---------------------------------------------------------------------------
static inline int16_t stk_right_x(stk_state_t const* s) {
return s->axes[1];
}
static inline int16_t stk_right_y(stk_state_t const* s) {
return s->axes[2];
}
static inline int16_t stk_throttle(stk_state_t const* s) {
return s->axes[3];
}
static inline int16_t stk_left_x(stk_state_t const* s) {
return s->axes[4];
}
// ---------------------------------------------------------------------------
// Button bitmask helpers (bit 0 = first switch, bit 23 = last)
// ---------------------------------------------------------------------------
static inline bool stk_button_pressed(stk_state_t const* s,
uint8_t index) {
if (index >= STK_NUM_BUTTONS)
return false;
return (s->buttons >> index) & 1;
}
// ---------------------------------------------------------------------------
// API
// ---------------------------------------------------------------------------
/**
* Open the HID radio device.
* config must remain valid for the lifetime of the open session.
* Returns 0 on success, -1 on failure.
*/
int stk_open(stk_config_t const* config);
/**
* Read the current radio state (non-blocking).
* Returns 0 on success, -1 on failure or no new data.
*/
int stk_read(stk_state_t* state);
/**
* Close the radio device. Safe to call multiple times.
*/
void stk_close(void);