added support for AP_ADC MAVLink packet

this adds AP_ADC, which sends raw ADC 16 bit values for all 6 ADC
channels at the Extra3 MAVLink stream rate. Extra3 was previously
unused

ArduPlane/GCS_Mavlink.pde

@@ -131,8 +131,7 @@ GCS_MAVLINK::data_stream_send(uint16_t freqMin, uint16_t freqMax)
 		}
 
 		if (freqLoopMatch(streamRateExtra3, freqMin, freqMax)){
-			// Available datastream
+			send_message(MSG_RAW_ADC);
-			//Serial.printf("mav8 %d\n", (int)streamRateExtra3.get());
 		}
 	}
 }

ArduPlane/Mavlink_Common.h

@@ -344,6 +344,20 @@ static bool mavlink_try_send_message(mavlink_channel_t chan, uint8_t id, uint16_
 			break;
 		}
 
+
+		case MSG_RAW_ADC:
+        {
+            CHECK_PAYLOAD_SIZE(AP_ADC);
+            mavlink_msg_ap_adc_send(chan, 
+                                    analogRead(BATTERY_PIN1),
+                                    analogRead(BATTERY_PIN2),
+                                    analogRead(BATTERY_PIN3),
+                                    analogRead(BATTERY_PIN4),
+                                    analogRead(AN4),
+                                    analogRead(AN5));
+            break;
+        }
+        
 		default:
 			break;
 	}
@@ -351,7 +365,7 @@ static bool mavlink_try_send_message(mavlink_channel_t chan, uint8_t id, uint16_
 }
 
 
-#define MAX_DEFERRED_MESSAGES 17 // should be at least equal to number of
+#define MAX_DEFERRED_MESSAGES 18 // should be at least equal to number of
                                  // switch types in mavlink_try_send_message()
 static struct mavlink_queue {
     uint8_t deferred_messages[MAX_DEFERRED_MESSAGES];

ArduPlane/defines.h

@@ -176,6 +176,7 @@
 #define MSG_GPS_RAW 0x64
 
 #define MSG_SERVO_OUT 0x70
+#define MSG_RAW_ADC   0x71
 
 #define MSG_PIN_REQUEST 0x80
 #define MSG_PIN_SET 0x81