Example Code for Arduino-Threshold interrupt

Hardware Preparation

• FireBeetle ESP32-E IoT Microcontroller(SKU: DFR0654) (or similar) x 1
• BMM150 Triple Axis Magnetometer (SKU: SEN0529)x 1
• Gravity-4P I2C/UART Sensor Cable(included with SEN0529) × 1
• Dupont Wires

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE
• Install SDK: click to enter FireBeetle ESP32-E IoT Microcontroller Wiki for SDK installation tutorial
• Download the DFRobot_BMM150 Library: DFRobot_BMM150 Library.
• For Arduino IDE V1.8.19 (or earlier), install the library manually: How to Add a Library
• For Arduino IDE V2.0.0 (or later), directly search for the "DFRobot_BMM150 Library" in the Library Manager and install it.

Wiring Diagram

Other Preparation Work

Ensure the I2C address is set correctly and the interrupt pin (INT) of the BMM150 is connected to the appropriate pin on the ESP32-E (e.g., pin 13 or 2 as per the code).

Sample Code

#include "DFRobot_BMM150.h"

DFRobot_BMM150_I2C bmm150(&Wire, I2C_ADDRESS_4);

/*i2c Address select, that CS and SDO pin select 1 or 0 indicates the high or low respectively. There are 4 combinations: 
 *I2C_ADDRESS_1 0x10  (CS:0 SDO:0)
 *I2C_ADDRESS_2 0x11  (CS:0 SDO:1)
 *I2C_ADDRESS_3 0x12  (CS:1 SDO:0)
 *I2C_ADDRESS_4 0x13  (CS:1 SDO:1) default i2c address */

#define BMM150_CS D3


volatile uint8_t interruptFlag = 0;
void myInterrupt(void)
{
  interruptFlag = 1;    // interrupt flag
  #if defined(ESP32) || defined(ESP8266)||defined(ARDUINO_SAM_ZERO)
    detachInterrupt(13);   //Connect to pin INT
  #else
    detachInterrupt(0);   
  #endif
}

void setup() 
{
  Serial.begin(115200);
  while(!Serial);
  while(bmm150.begin()){
    Serial.println("bmm150 init failed, Please try again!");
    delay(1000);
  } Serial.println("bmm150 init success!");

  bmm150.setOperationMode(BMM150_POWERMODE_NORMAL);//Normal mode

  bmm150.setPresetMode(BMM150_PRESETMODE_HIGHACCURACY);//High-accuracy mode

  bmm150.setRate(BMM150_DATA_RATE_10HZ);//rate of 10HZ

  bmm150.setMeasurementXYZ();//Default config of X-, Y-, and Z-axis

  bmm150.setThresholdInterrupt(LOW_THRESHOLD_INTERRUPT, 0, POLARITY_LOW);//trigger interrupt when below threshold

  #if defined(ESP32) || defined(ESP8266)||defined(ARDUINO_SAM_ZERO)

  pinMode(/*Pin */13 ,INPUT_PULLUP);//Low-polarity pull-up output
  attachInterrupt(/*interput io*/13, myInterrupt, LOW);

  pinMode(/*Pin */2 ,INPUT_PULLUP);

  attachInterrupt(/*Interrupt No*/0, /*function*/myInterrupt ,/*state*/LOW );//Set pin interrupt
  #endif

}

void loop() 
{
  if(interruptFlag == 1){
    sBmm150ThresholdData_t threshold = bmm150.getThresholdData();
    if(threshold.x != NO_DATA){
      Serial.print("mag x = "); Serial.print(threshold.x); Serial.println(" uT");
    }
    if(threshold.y != NO_DATA){
      Serial.print("mag y = "); Serial.print(threshold.y); Serial.println(" uT");
    }
    if(threshold.z != NO_DATA){
      Serial.print("mag z = "); Serial.print(threshold.z); Serial.println(" uT");
    }
    Serial.println();
    interruptFlag = 0;
    #if defined(ESP32) || defined(ESP8266)||defined(ARDUINO_SAM_ZERO)
      attachInterrupt(13, myInterrupt, LOW);
    #else
      attachInterrupt(0, myInterrupt ,LOW);
    #endif
  }
  delay(100);
}

Result

Burn sample code, rock the sensor to trigger threshold interrupt, and serial prints data change.