Add MSPHelper.getRTC() and MSPHelper.setRTC()

Functions for getting and setting the RTC. Not used for now, but
can be manually called from the debug console for testing RTC
related changes.

js/msp/MSPCodes.js

@@ -122,6 +122,9 @@ var MSPCodes = {
     MSP_SERVO_MIX_RULES:    241,
     MSP_SET_SERVO_MIX_RULE: 242,
 
+    MSP_RTC:                246,
+    MSP_SET_RTC:            247,
+
     MSP_EEPROM_WRITE:       250,
 
     MSP_DEBUGMSG:           253,

js/msp/MSPHelper.js

@@ -412,6 +412,16 @@ var mspHelper = (function (gui) {
             case MSPCodes.MSP_SET_SERVO_CONFIGURATION:
                 console.log('Servo Configuration saved');
                 break;
+            case MSPCodes.MSP_RTC:
+                if (data.length >= 6) {
+                    var seconds = data.getInt32(0, true);
+                    var millis = data.getUint16(4, true);
+                    console.log("RTC received: " + new Date(seconds * 1000 + millis));
+                }
+                break;
+            case MSPCodes.MSP_SET_RTC:
+                console.log('RTC set');
+                break;
             case MSPCodes.MSP_EEPROM_WRITE:
                 console.log('Settings Saved in EEPROM');
                 break;
@@ -2368,5 +2378,33 @@ var mspHelper = (function (gui) {
         });
     };
 
+    self.getRTC = function(callback) {
+        if (semver.gt(CONFIG.flightControllerVersion, "1.7.3")) {
+            MSP.send_message(MSPCodes.MSP_RTC, false, false, function(resp) {
+                var seconds = resp.data.read32();
+                var millis = resp.data.readU16();
+                if (callback) {
+                    callback(seconds, millis);
+                }
+            });
+        } else if (callback) {
+            callback(0, 0);
+        }
+    };
+
+    self.setRTC = function(callback) {
+        if (semver.gt(CONFIG.flightControllerVersion, "1.7.3")) {
+            var now = Date.now();
+            var secs = now / 1000;
+            var millis = now % 1000;
+            var data = [];
+            data.push32(secs);
+            data.push16(millis);
+            MSP.send_message(MSPCodes.MSP_SET_RTC, data, false, callback);
+        } else if (callback) {
+            callback();
+        }
+    };
+
     return self;
 })(GUI);