AP_Arming: Add servo voltage check, paramertise the Vcc check

libraries/AP_Arming/AP_Arming.cpp

@@ -17,11 +17,11 @@
 #include <AP_Notify/AP_Notify.h>
 #include <SRV_Channel/SRV_Channel.h>
 #include <GCS_MAVLink/GCS.h>
+#include <AP_BoardConfig/AP_BoardConfig.h>
 
 #define AP_ARMING_COMPASS_MAGFIELD_EXPECTED 530
 #define AP_ARMING_COMPASS_MAGFIELD_MIN  185     // 0.35 * 530 milligauss
 #define AP_ARMING_COMPASS_MAGFIELD_MAX  875     // 1.65 * 530 milligauss
-#define AP_ARMING_BOARD_VOLTAGE_MIN     4.3f
 #define AP_ARMING_BOARD_VOLTAGE_MAX     5.8f
 #define AP_ARMING_ACCEL_ERROR_THRESHOLD 0.75f
 #define AP_ARMING_AHRS_GPS_ERROR_MAX    10      // accept up to 10m difference between AHRS and GPS
@@ -525,15 +525,29 @@ bool AP_Arming::servo_checks(bool report) const
 
 bool AP_Arming::board_voltage_checks(bool report)
 {
-#if HAL_HAVE_BOARD_VOLTAGE
     // check board voltage
     if ((checks_to_perform & ARMING_CHECK_ALL) || (checks_to_perform & ARMING_CHECK_VOLTAGE)) {
-        if(((hal.analogin->board_voltage() < AP_ARMING_BOARD_VOLTAGE_MIN) || (hal.analogin->board_voltage() > AP_ARMING_BOARD_VOLTAGE_MAX))) {
+#if HAL_HAVE_BOARD_VOLTAGE
-            check_failed(ARMING_CHECK_VOLTAGE, report, "Check board voltage");
+        const float bus_voltage =  hal.analogin->board_voltage();
+        const float vbus_min = AP_BoardConfig::get_minimum_board_voltage();
+        if(((bus_voltage < vbus_min) || (bus_voltage > AP_ARMING_BOARD_VOLTAGE_MAX))) {
+            check_failed(ARMING_CHECK_VOLTAGE, report, "Board (%1.1fv) out of range %1.1f-%1.1fv", bus_voltage, vbus_min, AP_ARMING_BOARD_VOLTAGE_MAX);
+            return false;
+        }
+#endif // HAL_HAVE_BOARD_VOLTAGE
+
+#if HAL_HAVE_SERVO_VOLTAGE
+       const float vservo_min = AP_BoardConfig::get_minimum_servo_voltage();
+        if (is_positive(vservo_min)) {
+            const float servo_voltage =  hal.analogin->servorail_voltage();
+            if (servo_voltage < vservo_min) {
+                check_failed(ARMING_CHECK_VOLTAGE, report, "Servo voltage to low (%1.2fv < %1.2fv)", servo_voltage, vservo_min);
                 return false;
             }
         }
-#endif
+#endif // HAL_HAVE_SERVO_VOLTAGE
+    }
+
     return true;
 }