dshot: add 3D capability

src/drivers/dshot/DShot.cpp

@@ -530,11 +530,27 @@ bool DShot::updateOutputs(bool stop_motors, uint16_t outputs[MAX_ACTUATORS],
 
 	} else {
 		for (int i = 0; i < (int)num_outputs; i++) {
-			if (outputs[i] == DSHOT_DISARM_VALUE) {
+
+			uint16_t output = outputs[i];
+
+			// DShot 3D splits the throttle ranges in two.
+			// This is in terms of DShot values, code below is in terms of actuator_output
+			// Direction 1) 48 is the slowest, 1047 is the fastest.
+			// Direction 2) 1049 is the slowest, 2047 is the fastest.
+			if (_param_dshot_3d_enable.get()) {
+				if (output >= _param_dshot_3d_dead_l.get() && output <= _param_dshot_3d_dead_h.get()) {
+					output = DSHOT_DISARM_VALUE;
+
+				} else if (output < 1000 && output > 0) { //Todo: allow actuator 0 or dshot 48 to be used
+					output = 999 - output;
+				}
+			}
+
+			if (output == DSHOT_DISARM_VALUE) {
 				up_dshot_motor_command(i, DShot_cmd_motor_stop, i == requested_telemetry_index);
 
 			} else {
-				up_dshot_motor_data_set(i, math::min(outputs[i], static_cast<uint16_t>(DSHOT_MAX_THROTTLE)),
+				up_dshot_motor_data_set(i, math::min(output, static_cast<uint16_t>(DSHOT_MAX_THROTTLE)),
 							i == requested_telemetry_index);
 			}
 		}

src/drivers/dshot/DShot.h

@@ -231,6 +231,9 @@ private:
 	DEFINE_PARAMETERS(
 		(ParamInt<px4::params::DSHOT_CONFIG>)   _param_dshot_config,
 		(ParamFloat<px4::params::DSHOT_MIN>)    _param_dshot_min,
+		(ParamBool<px4::params::DSHOT_3D_ENABLE>) _param_dshot_3d_enable,
+		(ParamInt<px4::params::DSHOT_3D_DEAD_H>) _param_dshot_3d_dead_h,
+		(ParamInt<px4::params::DSHOT_3D_DEAD_L>) _param_dshot_3d_dead_l,
 		(ParamInt<px4::params::MOT_POLE_COUNT>) _param_mot_pole_count
 	)
 };

src/drivers/dshot/module.yaml

@@ -40,6 +40,37 @@ parameters:
             decimal: 2
             increment: 0.01
             default: 0.055
+        DSHOT_3D_ENABLE:
+            description:
+                short: Allows for 3d mode when using DShot and suitable mixer
+                long: |
+                    WARNING: ESC must be configured for 3D mode, and DSHOT_MIN set to 0.
+                    This splits the throttle ranges in two.
+                    Direction 1) 48 is the slowest, 1047 is the fastest.
+                    Direction 2) 1049 is the slowest, 2047 is the fastest.
+                    When mixer outputs 1000 or value inside DSHOT 3D deadband, DShot 0 is sent.
+            type: boolean
+            default: 0
+        DSHOT_3D_DEAD_H:
+            description:
+                short: DSHOT 3D deadband high
+                long: |
+                    When the actuator_output is between DSHOT_3D_DEAD_L and DSHOT_3D_DEAD_H, motor will not spin.
+                    This value is with respect to the mixer_module range (0-1999), not the DSHOT values.
+            type: int32
+            min: 1000
+            max: 1999
+            default: 1000
+        DSHOT_3D_DEAD_L:
+            description:
+                short: DSHOT 3D deadband low
+                long: |
+                    When the actuator_output is between DSHOT_3D_DEAD_L and DSHOT_3D_DEAD_H, motor will not spin.
+                    This value is with respect to the mixer_module range (0-1999), not the DSHOT values.
+            type: int32
+            min: 0
+            max: 1000
+            default: 1000
         MOT_POLE_COUNT: # only used by dshot so far, so keep it under the dshot group
             description:
                 short: Number of magnetic poles of the motors
@@ -51,4 +82,3 @@ parameters:
                     Typical motors for 5 inch props have 14 poles.
             type: int32
             default: 14
-