AP_Motors: added betaflight-x-reversed frame type

libraries/AP_Motors/AP_MotorsMatrix.cpp

@@ -517,6 +517,13 @@ void AP_MotorsMatrix::setup_motors(motor_frame_class frame_class, motor_frame_ty
                     add_motor(AP_MOTORS_MOT_3, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW,3);
                     add_motor(AP_MOTORS_MOT_4,  -45, AP_MOTORS_MATRIX_YAW_FACTOR_CW, 4);
                     break;
+                case MOTOR_FRAME_TYPE_BF_X_REV:
+                    // betaflight quad X order, reversed motors
+                    add_motor(AP_MOTORS_MOT_1,  135, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 2);
+                    add_motor(AP_MOTORS_MOT_2,   45, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  1);
+                    add_motor(AP_MOTORS_MOT_3, -135, AP_MOTORS_MATRIX_YAW_FACTOR_CW,  3);
+                    add_motor(AP_MOTORS_MOT_4,  -45, AP_MOTORS_MATRIX_YAW_FACTOR_CCW, 4);
+                    break;
                 case MOTOR_FRAME_TYPE_DJI_X:
                     // DJI quad X order
                     // see https://forum44.djicdn.com/data/attachment/forum/201711/26/172348bppvtt1ot1nrtp5j.jpg

libraries/AP_Motors/AP_Motors_Class.h

@@ -59,6 +59,7 @@ public:
         MOTOR_FRAME_TYPE_DJI_X = 13, // X frame, DJI ordering
         MOTOR_FRAME_TYPE_CW_X = 14, // X frame, clockwise ordering
         MOTOR_FRAME_TYPE_I = 15, // (sideways H) octo only
+        MOTOR_FRAME_TYPE_BF_X_REV = 18, // X frame, betaflight ordering, reversed motors
     };
 
     // Constructor
@@ -263,4 +264,4 @@ private:
 
 namespace AP {
     AP_Motors *motors();
-};
+};