Difference between revisions of "I/O Expander Shield with MCP23017"

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==Introduction==
 
  
 
[[File:IOExpand shield 1.jpg|400px]]
 
[[File:IOExpand shield 1.jpg|400px]]
 
[[File:IOExpand shield 2.jpg|400px]]
 
[[File:IOExpand shield 2.jpg|400px]]
 
==Schematic==
 
 
 
 
==Application Ideas==
 
 
'''test'''
 
<syntaxhighlight lang="c">
 
 
#include <Wire.h>
 
 
const byte  mcp_address=0x20;      // I2C Address of MCP23017 Chip
 
const byte  GPIOA=0x12;            // Register Address of Port A
 
const byte  GPIOB=0x13;            // Register Address of Port B
 
const byte  IODIRA=0x00;            // IODIRA register
 
const byte  IODIRB=0x01;            // IODIRB register
 
 
void setup()
 
{
 
  //Send settings to MCP device
 
  Wire.begin();              // join i2c bus (address optional for master)
 
  Wire.beginTransmission(mcp_address);
 
  Wire.write((byte)IODIRA); // IODIRA register
 
  Wire.write((byte)0x03); // set GPIOA-0/GPIOA-1 to inputs
 
  Wire.endTransmission();
 
}
 
 
void loop()
 
{
 
  Wire.beginTransmission(mcp_address);
 
  Wire.write((byte)GPIOA); // set MCP23017 memory pointer to GPIOB address
 
  Wire.endTransmission();
 
  Wire.requestFrom(0x20, 1); // request one byte of data from MCP20317
 
  int inputs=Wire.read(); // store the incoming byte into "inputs"
 
 
  if((inputs&0x01)==0)
 
  {
 
    Wire.beginTransmission(mcp_address);
 
    Wire.write(GPIOA);    // address bank A
 
    Wire.write((byte)0x04);  // value to send GPIOA-2 HIGH
 
    Wire.endTransmission();
 
  }
 
  if((inputs&0x02)==0)
 
  {
 
    Wire.beginTransmission(mcp_address);
 
    Wire.write(GPIOA);    // address bank A
 
    Wire.write((byte)0x08);  // value to send GPIOA-3 HIGH
 
    Wire.endTransmission();
 
  }
 
  else
 
  {
 
    Wire.beginTransmission(mcp_address);
 
    Wire.write(GPIOA);    // address bank A
 
    Wire.write((byte)0x00);  // value to send GPIOA LOW
 
    Wire.endTransmission();
 
  }
 
}
 
</syntaxhighlight>
 
 
==Resources==
 
*[http://cnlearn.linksprite.com/?p=5598 Turial]
 

Revision as of 06:41, 10 April 2014

IOExpand shield 1.jpg IOExpand shield 2.jpg