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));
+}