Add Library

libraries/Adafruit-MCP23017-Arduino-Library-master/examples/button/button.ino

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+#include <Wire.h>
+#include "Adafruit_MCP23017.h"
+
+// Basic pin reading and pullup test for the MCP23017 I/O expander
+// public domain!
+
+// Connect pin #12 of the expander to Analog 5 (i2c clock)
+// Connect pin #13 of the expander to Analog 4 (i2c data)
+// Connect pins #15, 16 and 17 of the expander to ground (address selection)
+// Connect pin #9 of the expander to 5V (power)
+// Connect pin #10 of the expander to ground (common ground)
+// Connect pin #18 through a ~10kohm resistor to 5V (reset pin, active low)
+
+// Input #0 is on pin 21 so connect a button or switch from there to ground
+
+Adafruit_MCP23017 mcp;
+  
+void setup() {  
+  mcp.begin();      // use default address 0
+
+  mcp.pinMode(0, INPUT);
+  mcp.pullUp(0, HIGH);  // turn on a 100K pullup internally
+
+  pinMode(13, OUTPUT);  // use the p13 LED as debugging
+}
+
+
+
+void loop() {
+  // The LED will 'echo' the button
+  digitalWrite(13, mcp.digitalRead(0));
+}

libraries/Adafruit-MCP23017-Arduino-Library-master/examples/interrupt/interrupt.ino

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+// Install the LowPower library for optional sleeping support.
+// See loop() function comments for details on usage.
+//#include <LowPower.h>
+
+#include <Wire.h>
+#include <Adafruit_MCP23017.h>
+
+Adafruit_MCP23017 mcp;
+
+byte ledPin=13;
+
+// Interrupts from the MCP will be handled by this PIN
+byte arduinoIntPin=3;
+
+// ... and this interrupt vector
+byte arduinoInterrupt=1;
+
+volatile boolean awakenByInterrupt = false;
+
+// Two pins at the MCP (Ports A/B where some buttons have been setup.)
+// Buttons connect the pin to grond, and pins are pulled up.
+byte mcpPinA=7;
+byte mcpPinB=15;
+
+void setup(){
+
+  Serial.begin(9600);
+  Serial.println("MCP23007 Interrupt Test");
+
+  pinMode(arduinoIntPin,INPUT);
+
+  mcp.begin();      // use default address 0
+  
+  // We mirror INTA and INTB, so that only one line is required between MCP and Arduino for int reporting
+  // The INTA/B will not be Floating 
+  // INTs will be signaled with a LOW
+  mcp.setupInterrupts(true,false,LOW);
+
+  // configuration for a button on port A
+  // interrupt will triger when the pin is taken to ground by a pushbutton
+  mcp.pinMode(mcpPinA, INPUT);
+  mcp.pullUp(mcpPinA, HIGH);  // turn on a 100K pullup internally
+  mcp.setupInterruptPin(mcpPinA,FALLING); 
+
+  // similar, but on port B.
+  mcp.pinMode(mcpPinB, INPUT);
+  mcp.pullUp(mcpPinB, HIGH);  // turn on a 100K pullup internall
+  mcp.setupInterruptPin(mcpPinB,FALLING);
+
+  // We will setup a pin for flashing from the int routine
+  pinMode(ledPin, OUTPUT);  // use the p13 LED as debugging
+  
+}
+
+// The int handler will just signal that the int has happen
+// we will do the work from the main loop.
+void intCallBack(){
+  awakenByInterrupt=true;
+}
+
+void handleInterrupt(){
+  
+  // Get more information from the MCP from the INT
+  uint8_t pin=mcp.getLastInterruptPin();
+  uint8_t val=mcp.getLastInterruptPinValue();
+  
+  // We will flash the led 1 or 2 times depending on the PIN that triggered the Interrupt
+  // 3 and 4 flases are supposed to be impossible conditions... just for debugging.
+  uint8_t flashes=4; 
+  if(pin==mcpPinA) flashes=1;
+  if(pin==mcpPinB) flashes=2;
+  if(val!=LOW) flashes=3;
+
+  // simulate some output associated to this
+  for(int i=0;i<flashes;i++){  
+    delay(100);
+    digitalWrite(ledPin,HIGH);
+    delay(100);
+    digitalWrite(ledPin,LOW);
+  }
+
+  // we have to wait for the interrupt condition to finish
+  // otherwise we might go to sleep with an ongoing condition and never wake up again.
+  // as, an action is required to clear the INT flag, and allow it to trigger again.
+  // see datasheet for datails.
+  while( ! (mcp.digitalRead(mcpPinB) && mcp.digitalRead(mcpPinA) ));
+  // and clean queued INT signal
+  cleanInterrupts();
+}
+
+// handy for interrupts triggered by buttons
+// normally signal a few due to bouncing issues
+void cleanInterrupts(){
+  EIFR=0x01;
+  awakenByInterrupt=false;
+}  
+
+/**
+ * main routine: sleep the arduino, and wake up on Interrups.
+ * the LowPower library, or similar is required for sleeping, but sleep is simulated here.
+ * It is actually posible to get the MCP to draw only 1uA while in standby as the datasheet claims,
+ * however there is no stadndby mode. Its all down to seting up each pin in a way that current does not flow.
+ * and you can wait for interrupts while waiting.
+ */
+void loop(){
+  
+  // enable interrupts before going to sleep/wait
+  // And we setup a callback for the arduino INT handler.
+  attachInterrupt(arduinoInterrupt,intCallBack,FALLING);
+  
+  // Simulate a deep sleep
+  while(!awakenByInterrupt);
+  // Or sleep the arduino, this lib is great, if you have it.
+  //LowPower.powerDown(SLEEP_1S, ADC_OFF, BOD_OFF);
+  
+  // disable interrupts while handling them.
+  detachInterrupt(arduinoInterrupt);
+  
+  if(awakenByInterrupt) handleInterrupt();
+}
+
+
+

libraries/Adafruit-MCP23017-Arduino-Library-master/examples/toggle/toggle.ino

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+#include <Wire.h>
+#include "Adafruit_MCP23017.h"
+
+// Basic pin reading and pullup test for the MCP23017 I/O expander
+// public domain!
+
+// Connect pin #12 of the expander to Analog 5 (i2c clock)
+// Connect pin #13 of the expander to Analog 4 (i2c data)
+// Connect pins #15, 16 and 17 of the expander to ground (address selection)
+// Connect pin #9 of the expander to 5V (power)
+// Connect pin #10 of the expander to ground (common ground)
+// Connect pin #18 through a ~10kohm resistor to 5V (reset pin, active low)
+
+// Output #0 is on pin 21 so connect an LED or whatever from that to ground
+
+Adafruit_MCP23017 mcp;
+  
+void setup() {  
+  mcp.begin();      // use default address 0
+
+  mcp.pinMode(0, OUTPUT);
+}
+
+
+// flip the pin #0 up and down
+
+void loop() {
+  delay(100);
+
+  mcp.digitalWrite(0, HIGH);
+
+  delay(100);
+
+  mcp.digitalWrite(0, LOW);
+}