Example Code for Arduino-Interrupt Polling

Hardware Preparation

• DFR0216-2 DFRduino UNO R3 with IO Expansion Shield and USB Cable A-B x 1
• DFR0626 MCP23017 IIC to 16 Digital IO Expansion Module x1
• DFR0029 Gravity: Digital Push Button x1
• Gravity: Bright LED Module x1

Software Preparation

• Download Arduino IDE: Click to download Arduino IDE
• Download the DFRobot_MCP23017 Library: DFRobot_MCP23017 Library
• About how to install the library?

Wiring Diagram

Other Preparation Work

Set PA0, PA1, PB6, PB7 to eChangeLevel, eFalling, eRising, eHighLevel interrupt modes respectively.

Sample Code

/*!
 * @file pollInterrupt.ino
 * @brief Set a pin of IO expansion board to interrupt mode, poll if there is an interrupt occurring on the pins of the port.
 * @n Experiment phenomenon: poll if there is an interrupt occurring on the port group(A, B, A+B), if there is, serial print the pin which is interrupted.
 *
 * @copyright   Copyright (c) 2010 DFRobot Co.Ltd (https://www.dfrobot.com)
 * @licence     The MIT License (MIT)
 * @author [Arya]([email protected])
 * @version  V1.0
 * @date  2019-07-18
 * @get from https://www.dfrobot.com
 * @url https://github.com/DFRobot/DFRobot_MCP23017
 */
#include <DFRobot_MCP23017.h>
DFRobot_MCP23017 mcp(Wire, 0x27);//constructor, change the Level of A2, A1, A0 via DIP switch to revise I2C address within 0x20~0x27.
//DFRobot_MCP23017 mcp;//use default parameter, Wire  0x27(default I2C address)

/*Interrupt service function, prototype void func(int index), index: the number of the pin that is interrupted*/
void func(int index){
  String description = mcp.pinDescription(/*pin = */index);
  Serial.print(description);
  Serial.println(" Interruption occurs!");
}

void setup() {
  Serial.begin(115200);
  
  /*wait for the chip to be initialized completely, and then exit*/
  while(mcp.begin() != 0){
    Serial.println("Initialization of the chip failed, please confirm that the chip connection is correct!");
    delay(1000);
  }

  /*Parameter mode, the available is shown below:  
  eLowLevel             eHighLevel             eRising                  eFalling                 eChangeLevel
  Low-level interrupt   High-level interrupt   Rising-edge interrupt    Falling-edge interrupt   Double-edge interrupts 
  Parameter cb Interrupt service function(with parameter)
  Prototype void func(int)
  */
  mcp.pinModeInterrupt(/*p = */mcp.eGPA0, /*mode = */mcp.eChangeLevel, /*cb = */func);//digital pin0(eGPA0), double edge interrupt, generate an interrupt when the status of pin0 changes, INTA output High level.
  mcp.pinModeInterrupt(/*p = */mcp.eGPA1, /*mode = */mcp.eFalling, /*cb = */func);//digital pin1(eGPA1), falling edge interrupt, generate an interrupt when the status of pin 1 changes from High to Low, INTA output High level.
  mcp.pinModeInterrupt(/*p = */mcp.eGPB7, /*mode = */mcp.eRising, /*cb = */func);//digital pin15(eGPB7), rising edge interrupt, generate an interrupt when the status of pin15 changes from Low to High, INTB output High level.
  mcp.pinModeInterrupt(/*p = */mcp.eGPB6, /*mode = */mcp.eHighLevel, /*cb = */func);//digital pin14(eGPB6), high level interrupt, generate an interrupt when the pin 14 is in high level, INTB output High level. 
}

void loop() {
  /*pollInterrupts function is used to poll if an interrupt occurs on a port group
  Parameter group, the available parameter is shown below: (default: eGPIOALL)
   eGPIOA         eGPIOB             eGPIOALL
   Port Group A   Port Group B       Port Group A+B
  */
  mcp.pollInterrupts();
 // delay(1000);
}

Result

Press the button connected with PA0, PA1, PB6, PB7 to trigger interrupt, and serial print the pins where interrupt happened.