i2c communication

use optic rotary encoder

master/master.ino

@@ -0,0 +1,62 @@
+#include <Wire.h>
+
+#define READ_BYTES_FROM_WIRE 1
+
+// needs global define
+#define DATA_STOP_BYTE 0x00
+#define HEADING_TRIGGER_BIT 1
+#define HEADING_HIGH_BIT 2
+#define ALTITUDE_TRIGGER_BIT 4
+#define ALTITUDE_HIGH_BIT 8
+
+struct device {
+  byte address;
+  String name;
+};
+
+struct device devices[] = {
+  {0x01, "althead"}
+};
+
+int numDevices = -1;
+
+void setup() {
+  numDevices = sizeof(devices) / sizeof(device);
+  
+  Wire.begin();
+
+  pinMode(LED_TX, OUTPUT);
+  digitalWrite(LED_TX, HIGH);
+  pinMode(LED_RX, OUTPUT);
+  digitalWrite(LED_RX, HIGH);
+}
+
+void loop() {
+  // loop through devices and ask for data
+  for (int i = 0; i < numDevices; i++) {
+    Wire.requestFrom(devices[i].address, READ_BYTES_FROM_WIRE);
+    while (Wire.available()) {
+      // device has data, ask as long for data as it sends
+      // if it never stops sending, we are fucked :)
+      byte data = Wire.read();
+      if (data != DATA_STOP_BYTE) {
+        if (data & ALTITUDE_TRIGGER_BIT) {
+          if (data & ALTITUDE_HIGH_BIT) {
+            Serial.println("Altitude up");
+          } else {
+            Serial.println("Altitude down");
+          }
+        } else if (data & HEADING_TRIGGER_BIT) {
+          if (data & HEADING_HIGH_BIT) {
+            Serial.println("Heading right");
+          } else {
+            Serial.println("Heading left");
+          }
+        } else {
+          // who are you?
+        }
+        Wire.requestFrom(devices[i].address, READ_BYTES_FROM_WIRE);
+      }
+    }
+  }
+}