Add parameter for configuring sbus pin number, disable sbus by default

docs/troubleshooting.md

@@ -13,7 +13,7 @@ Do the following:
 Do the following:
 
 * **Check the battery voltage**. Use a multimeter to measure the battery voltage. It should be in range of 3.7-4.2 V.
-* **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button to make sure you see the whole ESP32 startup output.
+* **Check if there are some startup errors**. Connect the ESP32 to the computer and check the Serial Monitor output. Use the Reset button or `reboot` command to see the whole startup output.
 * **Check the baudrate is correct**. If you see garbage characters in the Serial Monitor, make sure the baudrate is set to 115200.
 * **Make sure correct IMU model is chosen**. If using ICM-20948/MPU-6050 board, change `MPU9250` to `ICM20948`/`MPU6050` in the `imu.ino` file.
 * **Check if the console is working**. Perform `help` command in Serial Monitor. You should see the list of available commands. You can also access the console using QGroundControl *(Vehicle Setup* ⇒ *Analyze Tools* ⇒ *MAVLink Console)*.
@@ -35,5 +35,7 @@ Do the following:
 * **Check the propeller directions are correct**. Make sure your propeller types (A or B) are installed as on the picture:
   <img src="img/user/peter_ukhov-2/1.jpg" width="200">
 * **Check the remote control**. Using `rc` command, check the control values reflect your sticks movement. All the controls should change between -1 and 1, and throttle between 0 and 1.
-* If using SBUS receiver, **calibrate the RC**. Type `cr` command in Serial Monitor and follow the instructions.
+* **If using SBUS receiver**:
+  * **Define the used GPIO pin** in `RC_RX_PIN` parameter.
+  * **Calibrate the RC** using `cr` command in the console.
 * **Check the IMU output using QGroundControl**. Connect to the drone using QGroundControl on your computer. Go to the *Analyze* tab, *MAVLINK Inspector*. Plot the data from the `SCALED_IMU` message. The gyroscope and accelerometer data should change according to the drone movement.

docs/usage.md

@@ -143,8 +143,6 @@ If using brushless motors and ESCs:
 1. Set the appropriate PWM using the parameters: `MOT_PWM_STOP`, `MOT_PWM_MIN`, and `MOT_PWM_MAX` (1000, 1000, and 2000 is typical).
 2. Decrease the PWM frequency using the `MOT_PWM_FREQ` parameter (400 is typical).
 
-Reboot the drone to apply the changes.
-
 > [!CAUTION]
 > **Remove the props when configuring the motors!** If improperly configured, you may not be able to stop them.
 
@@ -195,11 +193,13 @@ There are several ways to control the drone's flight: using **smartphone** (Wi-F
 
 ### Control with a remote control
 
-Before using remote SBUS-connected remote control, you need to calibrate it:
+Before using SBUS-connected remote control you need to enable SBUS and calibrate it:
 
-1. Access the console using QGroundControl (recommended) or Serial Monitor.
+1. Connect to the drone using QGroundControl.
-2. Type `cr` command and follow the instructions.
+2. In parameters, set the `RC_RX_PIN` parameter to the GPIO pin number where the SBUS signal is connected, for example: 4. Negative value disables SBUS.
-3. Use the remote control to fly the drone!
+3. Reboot the drone to apply changes.
+4. Open the console, type `cr` command and follow the instructions to calibrate the remote control.
+5. Use the remote control to fly the drone!
 
 ### Control with a USB remote control
 

flix/parameters.ino

@@ -9,6 +9,7 @@
 extern int channelZero[16];
 extern int channelMax[16];
 extern int rollChannel, pitchChannel, throttleChannel, yawChannel, armedChannel, modeChannel;
+extern int rcRxPin;
 extern int wifiMode, udpLocalPort, udpRemotePort;
 extern float rcLossTimeout, descendTime;
 
@@ -78,6 +79,7 @@ Parameter parameters[] = {
 	{"MOT_PWM_MIN", &pwmMin},
 	{"MOT_PWM_MAX", &pwmMax},
 	// rc
+	{"RC_RX_PIN", &rcRxPin},
 	{"RC_ZERO_0", &channelZero[0]},
 	{"RC_ZERO_1", &channelZero[1]},
 	{"RC_ZERO_2", &channelZero[2]},

flix/rc.ino

@@ -7,6 +7,7 @@
 #include "util.h"
 
 SBUS rc(Serial2);
+int rcRxPin = -1; // -1 means disabled
 
 uint16_t channels[16]; // raw rc channels
 int channelZero[16]; // calibration zero values
@@ -19,11 +20,13 @@ float controlTime = NAN; // time of the last controls update
 int rollChannel = -1, pitchChannel = -1, throttleChannel = -1, yawChannel = -1, modeChannel = -1; // channel mapping
 
 void setupRC() {
+	if (rcRxPin < 0) return;
 	print("Setup RC\n");
-	rc.begin();
+	rc.begin(rcRxPin);
 }
 
 bool readRC() {
+	if (rcRxPin < 0) return false;
 	if (rc.read()) {
 		SBUSData data = rc.data();
 		for (int i = 0; i < 16; i++) channels[i] = data.ch[i]; // copy channels data
@@ -48,6 +51,10 @@ void normalizeRC() {
 }
 
 void calibrateRC() {
+	if (rcRxPin < 0) {
+		print("RC_RX_PIN = %d, set the RC pin!\n", rcRxPin);
+		return;
+	}
 	uint16_t zero[16];
 	uint16_t center[16];
 	uint16_t max[16];

gazebo/SBUS.h

@@ -13,7 +13,7 @@ class SBUS {
 public:
 	SBUS(HardwareSerial& bus, const bool inv = true) {};
 	SBUS(HardwareSerial& bus, const int8_t rxpin, const int8_t txpin, const bool inv = true) {};
-	void begin() {};
+	void begin(int rxpin = -1, int txpin = -1, bool inv = true, bool fast = false) {};
 	bool read() { return joystickInit(); };
 	SBUSData data() {
 		SBUSData data;