How to Use R-XSR Receiver: Examples, Pinouts, and Specs

The FrSky R-XSR Receiver is a lightweight and compact receiver designed for remote control applications, particularly in drones and model aircraft. It is a full-range receiver that supports telemetry, allowing users to monitor critical flight data in real time. The R-XSR is compatible with FrSky transmitters using the ACCST (Advanced Continuous Channel Shifting Technology) protocol, making it a popular choice for hobbyists and professionals alike.

• Remote-controlled drones and quadcopters
• Fixed-wing model aircraft
• FPV (First-Person View) racing drones
• Applications requiring telemetry feedback for real-time monitoring
• Compact builds where space and weight are critical

The following table outlines the key technical details of the FrSky R-XSR Receiver:

The R-XSR receiver has a compact pinout for easy integration into your projects. Below is the pin configuration:

1. Powering the Receiver: Connect the VCC pin to a regulated power source (4.0V - 10.0V) and the GND pin to the ground of your circuit.
2. Connecting to a Flight Controller:
   • Use the SBUS OUT pin to connect to the SBUS input of your flight controller.
   • If your flight controller supports telemetry, connect the S.Port pin to the corresponding telemetry port.
3. Binding the Receiver:
   • Power on the receiver while holding the bind button until the LED flashes red.
   • Put your FrSky transmitter into bind mode.
   • Once binding is successful, the LED will turn solid green.
4. Telemetry Setup:
   • Ensure your transmitter supports telemetry and is configured to receive data from the SmartPort.
   • Connect the S.Port pin to the telemetry input of your flight controller.

• Antenna Placement: Ensure the dual antennas are positioned at 90-degree angles to each other for optimal signal reception.
• Firmware Updates: Regularly update the receiver firmware via the SmartPort to ensure compatibility with your transmitter and access new features.
• Voltage Regulation: Use a stable power source within the specified voltage range to avoid damaging the receiver.
• Failsafe Configuration: Set up failsafe on your transmitter to ensure safe operation in case of signal loss.

The R-XSR receiver can be connected to an Arduino UNO for telemetry or signal processing. Below is an example code snippet for reading SBUS signals:

#include <SBUS.h>

// Create an SBUS object to handle communication with the receiver
SBUS sbus(Serial);

// Array to store channel data
uint16_t channels[16];
bool failsafe;
bool lostFrame;

void setup() {
  Serial.begin(100000); // SBUS communication uses 100,000 baud rate
  sbus.begin();         // Initialize SBUS communication
}

void loop() {
  if (sbus.read(&channels[0], &failsafe, &lostFrame)) {
    // Print channel data to the serial monitor
    for (int i = 0; i < 16; i++) {
      Serial.print("Channel ");
      Serial.print(i + 1);
      Serial.print(": ");
      Serial.println(channels[i]);
    }

    // Check for failsafe or lost frame conditions
    if (failsafe) {
      Serial.println("Failsafe activated!");
    }
    if (lostFrame) {
      Serial.println("Frame lost!");
    }
  }
  delay(100); // Add a small delay to avoid flooding the serial monitor
}

1. Receiver Not Binding to Transmitter:

   • Ensure the receiver and transmitter are both in D16 mode.
   • Check that the receiver firmware matches the transmitter firmware version.
   • Verify that the receiver is powered correctly and the bind button is pressed during power-up.

2. No Telemetry Data:

   • Confirm that the S.Port pin is connected to the correct telemetry port on the flight controller.
   • Ensure telemetry is enabled on your transmitter.
   • Update the receiver and transmitter firmware to the latest versions.

3. Signal Loss or Poor Range:

   • Check antenna placement and ensure they are not obstructed by carbon fiber or metal parts.
   • Inspect the antennas for damage and replace them if necessary.
   • Avoid operating in areas with high 2.4GHz interference.

4. Failsafe Not Working:

   • Configure failsafe settings on your transmitter and verify they are saved.
   • Test failsafe functionality by turning off the transmitter and observing the receiver's behavior.

Q: Can the R-XSR receiver be used with non-FrSky transmitters?
A: No, the R-XSR is designed to work exclusively with FrSky transmitters using the ACCST protocol.

Q: How do I update the firmware on the R-XSR?
A: Firmware updates can be performed via the SmartPort using a compatible FrSky transmitter or an external USB adapter.

Q: What is the range of the R-XSR receiver?
A: The R-XSR is a full-range receiver, capable of operating up to several kilometers under optimal conditions.

Q: Can I use the R-XSR with older flight controllers that only support PPM?
A: Yes, the R-XSR provides a CPPM output for compatibility with older flight controllers.

By following this documentation, you can effectively integrate and troubleshoot the FrSky R-XSR Receiver in your projects.