Example Code for Arduino-Reading Data via UART and Interrupts

Hardware Preparation

• DFR1222 FireBeetle 2 ESP32-C5 ×1
• SEN0694 Gravity: 9 DOF IMU Sensor ×1

Software Preparation

• Download and install Arduino IDE: Download Arduino IDE
• Download and install the DFRobot_Multi_DOF_IMU library: Download DFRobot_Multi_DOF_IMU Library
• Download and install the DFRobot_RTU library: Download DFRobot_RTU Library
• Library Installation Guide: View Installation Guide

Wiring Diagram

Connect the 9-axis IMU sensor to the ESP32-C5 as shown in the diagram. The main connections are as follows:

• Sensor pin “+” → ESP32-C5 3.3V
• Sensor pin “-” → ESP32-C5 GND
• Sensor pin “INT1” → ESP32-C5 GPIO27
• Sensor pin “INT3” → ESP32-C5 GPIO28
• Sensor UART pin “RX” → ESP32-C5 D3 (GPIO26)
• Sensor UART pin “TX” → ESP32-C5 D2 (GPIO8)
• Sensor DIP switch configuration: Set the communication mode to UART, and set the address to 0x4A

Sample Code

#include "DFRobot_Multi_DOF_IMU.h"

const uint8_t ADDR = 0x4A; 
DFRobot_Multi_DOF_IMU_UART imu(DFRobot_Multi_DOF_IMU::eSensorModel9DOF, &Serial1, 9600, ADDR, /*rx*/ 8, /*tx*/ 26);

// Interrupt pin definitions
const uint8_t INT1_PIN = 27;   
const uint8_t INT3_PIN = 28;   

// Interrupt flags
volatile bool int1Flag = false;
volatile bool int3Flag = false;

// Interrupt service routines (must be placed in IRAM)
void IRAM_ATTR int1ISR() { int1Flag = true; }
void IRAM_ATTR int3ISR() { int3Flag = true; }

void setup() {
  Serial.begin(115200);
  while (!Serial) delay(10);
  Serial.println("\n=== ESP32 9DOF IMU UART Example ===\n");

  // Initialize sensor
  Serial.print("Initializing IMU... ");
  while (!imu.begin()) {
    Serial.println("FAILED! Check wiring and address.");
    delay(1000);
  }
  Serial.println("OK");

  // Configure sensor parameters
  Serial.print("Set normal mode... ");
  imu.setSensorMode(DFRobot_Multi_DOF_IMU::eNormalMode);
  Serial.println("OK");

  Serial.print("Set accel range ±2G... ");
  imu.setAccelRange(DFRobot_Multi_DOF_IMU::eAccelRange2G);
  Serial.println("OK");

  Serial.print("Set gyro range ±250dps... ");
  imu.setGyroRange(DFRobot_Multi_DOF_IMU::eGyroRange250DPS);
  Serial.println("OK");

  // Configure interrupts
  Serial.print("Config INT1 (data ready)... ");
  imu.setInt(DFRobot_Multi_DOF_IMU::eImuIntPin1, DFRobot_Multi_DOF_IMU::eInt1_2DataReady);
  Serial.println("OK");

  Serial.print("Config INT3 (data ready)... ");
  imu.setInt(DFRobot_Multi_DOF_IMU::eImuIntPin3, DFRobot_Multi_DOF_IMU::eInt3DataReady);
  Serial.println("OK");

  // Attach interrupts
  attachInterrupt(digitalPinToInterrupt(INT1_PIN), int1ISR, RISING);
  attachInterrupt(digitalPinToInterrupt(INT3_PIN), int3ISR, RISING);
  Serial.println("Interrupts attached (rising edge)\n");

  Serial.println("Configuration complete. Reading data...\n");
}

void loop() {
  if (int1Flag || int3Flag) {
    // Read interrupt status
    uint16_t int1Status = imu.getIntStatus(DFRobot_Multi_DOF_IMU::eImuIntPin1);
    uint16_t int3Status = imu.getIntStatus(DFRobot_Multi_DOF_IMU::eImuIntPin3);

    bool int1Ready = (int1Status & INT1_2_INT_STATUS_DRDY) != 0;
    bool int3Ready = (int3Status & INT3_INT_STATUS_DRDY) != 0;

    // Read data only when both interrupts are ready (ensure all sensor data updated)
    if (int1Ready && int3Ready) {
      int1Flag = false;
      int3Flag = false;

      DFRobot_Multi_DOF_IMU::sSensorData_t accel, gyro, mag;
      if (imu.get9dofData(&accel, &gyro, &mag)) {
        
        Serial.print("ACCEL(g): ");
        Serial.print(accel.x, 3); Serial.print(", ");
        Serial.print(accel.y, 3); Serial.print(", ");
        Serial.println(accel.z, 3);

        Serial.print("GYRO(dps): ");
        Serial.print(gyro.x, 2); Serial.print(", ");
        Serial.print(gyro.y, 2); Serial.print(", ");
        Serial.println(gyro.z, 2); 
        Serial.print("MAG(uT): ");
        Serial.print(mag.x, 2); Serial.print(", ");
        Serial.print(mag.y, 2); Serial.print(", ");
        Serial.println(mag.z, 2);
        Serial.println();
      } else {
        Serial.println("Failed to read 9DOF data!");
      }
    } else {
      // Clear flags for interrupts that are not ready
      if (int1Flag && !int1Ready) int1Flag = false;
      if (int3Flag && !int3Ready) int3Flag = false;
    }
  }

}

Result