79 lines
2.2 KiB
C++
79 lines
2.2 KiB
C++
#include <Wire.h>
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//fuzzywobble.com 2012
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//this code turns every PCF8575 pin into an input (without interrupt)
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//datasheet - http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=pcf8575&fileType=pdf
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//i2c code adapted from i2c_dio_pcf8575c.cpp - Arduino class library for TI PCF8575C 16-bit I2C I/O expander
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//address is |0100|A0|A1|A2|
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int address = 0x20; //0100000 (7bit)
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uint16_t dataReceive; //16bit data received
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uint16_t dataSend; //16bit data sent
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void setup(){
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Wire.begin();
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Serial.begin(9600);
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//turn pins to input in setup
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//if bit = 0, pin functions as input or an output that is off
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//if bit = 1, pin functions as an output that is on
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dataSend = word(B01111111,B11111111); //turn every pin to output
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pcf8575_write(dataSend); //turn the pcf8575 pins to output
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}
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void loop(){
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dataSend = word(B01111110,B01110001);
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pcf8575_write(dataSend); //read the pcf8575 pins
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delay(100);
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dataSend = word(B00000000,B00000000);
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pcf8575_write(dataSend); //read the pcf8575 pins
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delay(100);
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}
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//custom functions -----------------------------
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//I2C/TWI success (transaction was successful).
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static const uint8_t ku8TWISuccess = 0;
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//I2C/TWI device not present (address sent, NACK received).
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static const uint8_t ku8TWIDeviceNACK = 2;
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//I2C/TWI data not received (data sent, NACK received).
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static const uint8_t ku8TWIDataNACK = 3;
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//I2C/TWI other error.
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static const uint8_t ku8TWIError = 4;
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uint8_t error;
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void pcf8575_write(uint16_t dt){
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Wire.beginTransmission(address);
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Wire.write(lowByte(dt));
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Wire.write(highByte(dt));
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error = Wire.endTransmission();
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if(error == ku8TWISuccess){ //okay!
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}
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else{ //we have an error
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//do something here if you like
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}
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}
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uint8_t hi,lo;
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uint16_t pcf8575_read(){
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Wire.beginTransmission(address);
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error = Wire.endTransmission();
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if(error == ku8TWISuccess){ //okay!
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Wire.requestFrom(address,2);
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if(Wire.available()){
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lo = Wire.read();
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hi = Wire.read();
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return(word(hi,lo)); //joing bytes
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}
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else{//error
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//do something here if you like
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}
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}
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else{ //error
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//do something here if you like
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}
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}
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