fixed airspeed sensor for ArduPlane on APM2

we were trying to use a non-existant ADC chip!

ArduPlane/ArduPlane.pde

@@ -131,7 +131,9 @@ static AP_Int8		*flight_modes = &g.flight_mode1;
 #if HIL_MODE == HIL_MODE_DISABLED
 
 // real sensors
+#if CONFIG_ADC == ENABLED
 static AP_ADC_ADS7844          adc;
+#endif
 
 #ifdef DESKTOP_BUILD
 AP_Baro_BMP085_HIL      barometer;
@@ -224,9 +226,9 @@ ModeFilter sonar_mode_filter;
 
 #if CONFIG_PITOT_SOURCE == PITOT_SOURCE_ADC
 AP_AnalogSource_ADC pitot_analog_source( &adc,
-                        CONFIG_PITOT_SOURCE_ADC_CHANNEL, 0.25);
+                        CONFIG_PITOT_SOURCE_ADC_CHANNEL, 1.0);
 #elif CONFIG_PITOT_SOURCE == PITOT_SOURCE_ANALOG_PIN
-AP_AnalogSource_Arduino pitot_analog_source(CONFIG_PITOT_SOURCE_ANALOG_PIN);
+AP_AnalogSource_Arduino pitot_analog_source(CONFIG_PITOT_SOURCE_ANALOG_PIN, 4.0);
 #endif
 
 #if SONAR_TYPE == MAX_SONAR_XL

ArduPlane/config.h

@@ -65,6 +65,7 @@
 # define CONFIG_RELAY      DISABLED
 # define MAG_ORIENTATION   AP_COMPASS_APM2_SHIELD
 # define CONFIG_SONAR_SOURCE SONAR_SOURCE_ANALOG_PIN
+# define CONFIG_PITOT_SOURCE PITOT_SOURCE_ANALOG_PIN
 # ifdef APM2_BETA_HARDWARE
 #  define CONFIG_BARO     AP_BARO_BMP085
 # else // APM2 Production Hardware (default)

ArduPlane/sensors.pde

@@ -77,10 +77,10 @@ static void read_airspeed(void)
             // calibration before we can use it. This isn't as
             // accurate as the 50 point average in zero_airspeed(),
             // but it is better than using it uncalibrated
-            airspeed_raw = (float)adc.Ch(AIRSPEED_CH);
+            airspeed_raw = pitot_analog_source.read();
             g.airspeed_offset.set_and_save(airspeed_raw);
 		}
-		airspeed_raw 		= (adc.Ch(AIRSPEED_CH) * 0.1) + (airspeed_raw * 0.9);
+		airspeed_raw 		= (pitot_analog_source.read() * 0.1) + (airspeed_raw * 0.9);
 		airspeed_pressure 	= max((airspeed_raw - g.airspeed_offset), 0);
 		airspeed 			= sqrt(airspeed_pressure * g.airspeed_ratio) * 100;
 	#endif
@@ -92,10 +92,10 @@ static void zero_airspeed(void)
 {
     float sum = 0;
     int c;
-	airspeed_raw = adc.Ch(AIRSPEED_CH);
+	airspeed_raw = pitot_analog_source.read();
 	for(c = 0; c < 250; c++) {
 		delay(2);
-		sum += adc.Ch(AIRSPEED_CH);
+		sum += pitot_analog_source.read();
 	}
     sum /= c;
 	g.airspeed_offset.set_and_save((int16_t)sum);

ArduPlane/system.pde

@@ -177,7 +177,9 @@ static void init_ardupilot()
 
 #if HIL_MODE != HIL_MODE_ATTITUDE
 
+#if CONFIG_ADC == ENABLED
     adc.Init(&timer_scheduler);      // APM ADC library initialization
+#endif
 
 	barometer.init(&timer_scheduler);
 

ArduPlane/test.pde

@@ -626,8 +626,8 @@ test_mag(uint8_t argc, const Menu::arg *argv)
 static int8_t
 test_airspeed(uint8_t argc, const Menu::arg *argv)
 {
-    float airspeed_ch = adc.Ch(AIRSPEED_CH);
-	// Serial.println(adc.Ch(AIRSPEED_CH));
+    float airspeed_ch = pitot_analog_source.read();
+	// Serial.println(pitot_analog_source.read());
     Serial.printf_P(PSTR("airspeed_ch: %.1f\n"), airspeed_ch);
 
 	if (g.airspeed_enabled == false){