adding files

i2c_encoder/encoder.cpp

@@ -0,0 +1,28 @@
+#include "encoder.h"
+
+//  public:
+
+// constructor : sets pins as inputs and turns on pullup resistors
+RotaryEncoder::RotaryEncoder( const String& argName, int argClkPin, int argDtPin, int argPinMode) : name(argName), clkPin ( argClkPin), dtPin( argDtPin ) 
+{
+   // set pin a and b to be input with pull up enabled
+   pinMode(clkPin, argPinMode);
+   pinMode(dtPin, argPinMode);
+   
+   position = 0;
+}
+
+void RotaryEncoder::update(void) 
+{
+   digitalRead(dtPin) ? position++ : position--;
+}
+
+int RotaryEncoder::getPosition ()
+{
+   return position;
+}
+
+void RotaryEncoder::clearPosition()
+{
+   position = 0;
+}

i2c_encoder/encoder.h

@@ -0,0 +1,64 @@
+ #ifndef __C_ROTARY_ENCODER_H__
+#define __C_ROTARY_ENCODER_H__
+
+#include <Arduino.h>
+
+class RotaryEncoder {
+    /*
+      wraps encoder setup and update functions in a class
+
+      !!! NOTE : user must call the encoders update method from an
+      interrupt function himself! i.e. user must attach an interrupt to the
+      encoder pin A and call the encoder update method from within the
+      interrupt
+
+      uses Arduino pull-ups on A & B channel outputs
+      turning on the pull-ups saves having to hook up resistors
+      to the A & B channel outputs
+
+      // ------------------------------------------------------------------------------------------------
+      // Example usage :
+      // ------------------------------------------------------------------------------------------------
+          #include "Encoder.h"
+
+          Encoder encoder(2, 4);
+
+          void setup() {
+              attachInterrupt(0, doEncoder, CHANGE);
+              Serial.begin (115200);
+              Serial.println("start");
+          }
+
+          void loop(){
+              // do some stuff here - the joy of interrupts is that they take care of themselves
+          }
+
+          void doEncoder(){
+              encoder.update();
+              Serial.println( encoder.getPosition() );
+          }
+      // ------------------------------------------------------------------------------------------------
+      // Example usage end
+      // ------------------------------------------------------------------------------------------------
+    */
+  public:
+
+    // constructor : sets pins as inputs and turns on pullup resistors
+
+    RotaryEncoder( const String& argName, int argClkPin, int argDtPin, int argPinMode = INPUT_PULLUP);
+	~RotaryEncoder() {};
+	
+    // call this from your interrupt function
+    void update();
+    int getPosition();
+    void clearPosition();
+
+  private:
+
+    String name;
+    volatile int position;
+    int clkPin;  // clock pin
+    int dtPin;   // direction pin
+};
+
+#endif // __C_ROTARY_ENCODER_H__

i2c_encoder/i2c_encoder.ino

@@ -0,0 +1,58 @@
+#include <Wire.h>
+#include "encoder.h"
+
+constexpr auto kSlaveAddress = 0x08;       // I2C address for Arduino
+constexpr auto kXEncoderClockPin = 2;
+constexpr auto kXEncoderDirectionPin = 8;
+constexpr auto kZEncoderClockPin = 3;
+constexpr auto kZEncoderDirectionPin = 9;
+
+static void x_isr(void);
+static void z_isr(void);
+static void sendData(void);
+
+static RotaryEncoder x_encoder{"X", kXEncoderClockPin, kXEncoderDirectionPin, INPUT};
+static RotaryEncoder z_encoder{"Z", kZEncoderClockPin, kZEncoderDirectionPin, INPUT_PULLUP};
+static char data[4] = {0, 0, 0, 0};
+
+void setup(){
+  //Serial.begin(38400);
+  //Serial.setTimeout(500);
+  //Serial.println("setup()");
+
+  Wire.begin(kSlaveAddress);
+  Wire.onRequest(sendData);
+
+  attachInterrupt(digitalPinToInterrupt(kXEncoderClockPin), x_isr, RISING);
+  attachInterrupt(digitalPinToInterrupt(kZEncoderClockPin), z_isr, RISING);
+}
+void loop() {
+  /*Serial.println(x_encoder.getPosition());
+  Serial.println(z_encoder.getPosition());
+  delay(250);*/
+}
+
+// Handle request to send I2C data
+void sendData() { 
+  int x_pos = x_encoder.getPosition();
+  int z_pos = z_encoder.getPosition();
+  
+  data[0] = 0x00ff & x_pos;
+  data[1] = (0xff00 & x_pos) >> 8;
+  
+  data[2] = 0x00ff & z_pos;
+  data[3] = (0xff00 & z_pos) >> 8;
+
+
+  Wire.write(data, 4);
+}
+
+static void x_isr(void)
+{
+  x_encoder.update();
+}
+
+static void z_isr(void)
+{
+  z_encoder.update();
+}