35 lines
847 B
Arduino
35 lines
847 B
Arduino
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#include <Wire.h>
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#include "Adafruit_MCP23017.h"
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// Basic pin reading and pullup test for the MCP23017 I/O expander
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// public domain!
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// Connect pin #12 of the expander to Analog 5 (i2c clock)
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// Connect pin #13 of the expander to Analog 4 (i2c data)
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// Connect pins #15, 16 and 17 of the expander to ground (address selection)
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// Connect pin #9 of the expander to 5V (power)
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// Connect pin #10 of the expander to ground (common ground)
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// Connect pin #18 through a ~10kohm resistor to 5V (reset pin, active low)
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// Output #0 is on pin 21 so connect an LED or whatever from that to ground
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Adafruit_MCP23017 mcp;
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void setup() {
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mcp.begin(); // use default address 0
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mcp.pinMode(0, OUTPUT);
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}
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// flip the pin #0 up and down
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void loop() {
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delay(100);
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mcp.digitalWrite(0, HIGH);
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delay(100);
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mcp.digitalWrite(0, LOW);
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}
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