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

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

Revision as of 06:35, 10 April 2014

Introduction

IOExpand shield 1.jpg IOExpand shield 2.jpg

Schematic

Application Ideas

test <syntaxhighlight lang="c">

  1. 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