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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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| − | ==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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| − |
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| − | ==Resources==
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| − | *[http://cnlearn.linksprite.com/?p=5598 Turial]
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