AP_BoardConfig: Add minimum board and servo voltage parameters

libraries/AP_BoardConfig/AP_BoardConfig.cpp

@@ -100,6 +100,10 @@
 #define BOARD_PWM_COUNT_DEFAULT 8
 #endif
 
+#ifndef BOARD_CONFIG_BOARD_VOLTAGE_MIN
+#define BOARD_CONFIG_BOARD_VOLTAGE_MIN 4.3f
+#endif
+
 extern const AP_HAL::HAL& hal;
 AP_BoardConfig *AP_BoardConfig::instance;
 
@@ -226,6 +230,29 @@ const AP_Param::GroupInfo AP_BoardConfig::var_info[] = {
     // @Path: ../AP_RTC/AP_RTC.cpp
     AP_SUBGROUPINFO(rtc, "RTC", 14, AP_BoardConfig, AP_RTC),
 
+#if HAL_HAVE_BOARD_VOLTAGE
+    // @Param: VBUS_MIN
+    // @DisplayName: Autopilot board voltage requirement
+    // @Description: Minimum voltage on the autopilot power rail to allow the aircraft to arm. 0 to disable the check.
+    // @Units: V
+    // @Range: 4.0 5.5
+    // Increment 0.1
+    // @User: Advanced
+    AP_GROUPINFO("VBUS_MIN",    15,     AP_BoardConfig,  _vbus_min,  BOARD_CONFIG_BOARD_VOLTAGE_MIN),
+
+#endif
+
+#if HAL_HAVE_SERVO_VOLTAGE
+    // @Param: VSERVO_MIN
+    // @DisplayName: Servo voltage requirement
+    // @Description: Minimum voltage on the servo rail to allow the aircraft to arm. 0 to disable the check.
+    // @Units: V
+    // @Range: 3.3 12.0
+    // Increment 0.1
+    // @User: Advanced
+    AP_GROUPINFO("VSERVO_MIN",    16,     AP_BoardConfig, _vservo_min,  0),
+#endif
+
     AP_GROUPEND
 };
 

libraries/AP_BoardConfig/AP_BoardConfig.h

@@ -143,6 +143,19 @@ public:
 #endif
     }
 
+#if HAL_HAVE_BOARD_VOLTAGE
+    // get minimum board voltage
+    static float get_minimum_board_voltage(void) {
+        return instance?instance->_vbus_min.get():0;
+    }
+#endif
+
+#if HAL_HAVE_SERVO_VOLTAGE
+    // get minimum servo voltage
+    static float get_minimum_servo_voltage(void) {
+        return instance?instance->_vservo_min.get():0;
+    }
+#endif
     
 private:
     static AP_BoardConfig *instance;
@@ -207,4 +220,12 @@ private:
 
     // real-time-clock; private because access is via the singleton
     AP_RTC rtc;
+
+#if HAL_HAVE_BOARD_VOLTAGE
+    AP_Float _vbus_min;
+#endif
+
+#if HAL_HAVE_SERVO_VOLTAGE
+    AP_Float _vservo_min;
+#endif
 };