Added some more projects and libraries.

PCF8575_i2c_Arduino/PCF8575_i2c_Arduino.ino

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