Interrupt Example

Description

The Example2_Interrupts.ino example file can be accessed from the File > Examples > SparkFun TMAG5273 Arduino Library > Example2_Interrupts drop-down menu. This example builds upon the previous code in Example1_BasicReadings.ino. Instead of constantly streaming the sensor values from the TMAG5273, the microcontroller enables a magnetic threshold interrupt on the x-axis. Then, it waits until an interrupt is triggered on the INT pin before the data is retrieved through the I²C interface.

Example2_Interrupts.ino

Code Verification

The code modification was last verified to be functional under the following parameters:

Arduino IDE Version: 2.2.1
Arduino Library Version: 1.0.3

Hardware Platform:
- SparkFun RedBoard Plus
- SparkFun Linear 3D Hall-Effect Sensor - TMAG5273 (Qwiic)
- SparkFun Mini Linear 3D Hall-Effect Sensor - TMAG5273 (Qwiic)

Required Modification

This code was developed to be utilized with the ESP32 on the IoT Motor Driver. Users will need to modify the example code, to utilize the interrupt pins of the ATmega328P on the RedBoard Plus. Replace ~~uint8_t intPin = 4;~~ with uint8_t intPin = 2; to utilize the D2 pin on the RedBoard Plus, which can handle interrupts.

Original Code:

// Interrupt pin used
// NOTE: This pin is specific to the SparkFun IoT Motor Driver
uint8_t intPin = 4;

Modified Code:

// Interrupt pin used
// NOTE: This pin is specific to the SparkFun IoT Motor Driver
uint8_t intPin = 2;

#include <Wire.h>               // Used to establish serial communication on the I2C bus
#include "SparkFun_TMAG5273_Arduino_Library.h"  // Used to send and recieve specific information from our sensor

TMAG5273 sensor;  // Initialize hall-effect sensor

// I2C default address
uint8_t i2cAddress = TMAG5273_I2C_ADDRESS_INITIAL;

// Interrupt pin used
// NOTE: This pin is specific to the SparkFun IoT Motor Driver
uint8_t intPin = 4;

// Start the flag as false
bool interruptFlag = false;

// ISR to print what interrupt was triggered
void isr1() 
{
  interruptFlag = true;
}


void setup() 
{
  Wire.begin();
  // Start serial communication at 115200 baud
  Serial.begin(115200);

  // Configure Interrupt Pin
  pinMode(intPin, INPUT);
  // Attach interrupt to pin 4 as a digital, falling pin
  attachInterrupt(digitalPinToInterrupt(intPin), isr1, CHANGE);

  // Begin example of the magnetic sensor code (and add whitespace for easy reading)
  Serial.println("TMAG5273 Example 2: Interrupts");
  Serial.println("");
  // If begin is successful (0), then start example
  if (sensor.begin(i2cAddress, Wire) == true)
  {
    Serial.println("Begin");
  } 
  else  // Otherwise, infinite loop
  {
    Serial.println("Device failed to setup - Freezing code.");
    while (1);  // Runs forever
  }

  // Set interrupt through !INT
  sensor.setInterruptMode(TMAG5273_INTERRUPT_THROUGH_INT);

  // Set the !INT pin state - pulse for 10us
  sensor.setIntPinState(true);

  // Enable the interrupt response for the thresholds
  sensor.setThresholdEn(true);

  //int pinStatus = sensor.getInterruptPinStatus();
  pinMode(intPin, INPUT);

  // Set X, Y, Z, and T Thresholds for interrupt to be triggered
  sensor.setXThreshold(5);            // mT
  //sensor.setYThreshold(5);            // mT
  //sensor.setZThreshold(5);            // mT
  //sensor.setTemperatureThreshold(50);  // C

  Serial.print("X Threshold Set: ");
  Serial.println(sensor.getXThreshold());
}

/* To use the other thresholds, simply change the names and use the other functions: 
- sensor.getYThreshold();
- sensor.getZThreshold();
- sensor.getTemperatureThreshold();
*/

void loop()
{
  if (interruptFlag == true) 
  {
    interruptFlag = false;
    Serial.println("X Threshold Reached!");

    int xThresh = sensor.getXThreshold();
    Serial.print("X Threshold: ");
    Serial.println(xThresh);

    if (sensor.getMagneticChannel() != 0)  // Checks if mag channels are on - turns on in setup
    {
      float magX = sensor.getXData();
      float magY = sensor.getYData();
      float magZ = sensor.getZData();
      float temp = sensor.getTemp();

      Serial.print("(");
      Serial.print(magX);
      Serial.print(", ");
      Serial.print(magY);
      Serial.print(", ");
      Serial.print(magZ);
      Serial.println(") mT");
      Serial.print(temp);
      Serial.println(" °C");
    } 
    else 
    {
      Serial.println("Mag Channels disabled, stopping..");
      while (1);
    }
  }
  else
  {
    Serial.println("Checking for Interrupts...");
  }

  delay(500);

}

Hardware Connections

For this example, users simply need to connect their Qwiic Hall-Effect Sensor board to their microcontroller, utilizing the I²C interface and interrupt pin. Users can easily connect the I²C interface with the Qwiic connection system on their boards. To connect the interrupt pin, we recommend utilizing an IC-hook for a temporary connection.

The mini sensor connected to a RedBoard Plus

The Qwiic Hall-Effect Sensor boards are connected to a RedBoard Plus, with a Qwiic cable and an IC-hook.

Pin Connections

For users with a development board without a Qwiic connector, the table below illustrates the required pin connections. Make sure that the logic-level of the sensor is compatible with the development board that is being connected.

Sensor Pin	Microcontroller Pin	RedBoard/Uno
`INT`	Interrupt Pin	`D2`
`SCL`	I²C - Serial Clock	`SCL`/`A5`
`SDA`	I²C - Serial Data	`SDA`/`A4`
`3V3`	Power: 1.7 to 3.6V	`3.3V`
`GND`	Ground	`GND`

Serial Monitor

This example waits until an interrupt is triggered by the magnetic threshold before data is retrieved from the TMAG5273 sensor. The data is then displayed in the Serial Monitor.

Tip

For this example to work, users will need to move a magnet near the sensor to trigger the interrupt.

Warning

The casing of rare Earth magnets is often conductive. Users should take precautions to avoid shorting out the components or electrical contacts with these types of magnets.