MQTT keepalive and reset devices on master boot

close #1

rotator/rotator.ino

@@ -12,6 +12,7 @@
 
 // needs global define
 #define DATA_STOP_BYTE 0x00
+#define DATA_RESET_BYTE 0xFF
 #define ROTATOR1_TRIGGER_BIT 1
 #define ROTATOR1_HIGH_BIT 2
 #define ROTATOR2_TRIGGER_BIT 4
@@ -95,6 +96,17 @@ void i2cRequest() {
   }
 }
 
+void i2cReceive(int bytes) {
+  for (int i = 0; i < bytes && Wire.available(); i++) {
+    byte data = Wire.read();
+    if (data == DATA_RESET_BYTE) {
+      writerPos = readerPos = 0;
+    } else {
+      // nothing else yet implemented
+    }
+  }
+}
+
 uint8_t address = 0;
 void setup() {
   Serial.begin(115200);
@@ -120,6 +132,7 @@ void setup() {
 
   Wire.begin(address);
   Wire.onRequest(i2cRequest);
+  Wire.onReceive(i2cReceive);
 }
 
 void loop() {