32 lines
920 B
Arduino
32 lines
920 B
Arduino
|
#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));
|
||
|
|
}
|