microbit: Support for bonding only available in pairing mode

Update to BLE initialisation code. Ability to initiate pairing is now
restricted to pairing mode.

inc/MicroBitBLEManager.h

@@ -72,7 +72,7 @@ class MicroBitBLEManager
       * uBit.init();
       * @endcode
       */
-    void init(ManagedString deviceName, ManagedString serialNumber);
+    void init(ManagedString deviceName, ManagedString serialNumber, bool enableBonding);
 
     /**
      * Change the output power level of the transmitter to the given value.

source/MicroBit.cpp

@@ -133,13 +133,6 @@ void MicroBit::init()
     // Seed our random number generator
     seedRandom();
 
-#if CONFIG_ENABLED(MICROBIT_BLE_ENABLED)
-    // Start the BLE stack.
-    bleManager.init(this->getName(), this->getSerial());
-
-    ble = bleManager.ble;
-#endif
-
     // Start refreshing the Matrix Display
     systemTicker.attach(this, &MicroBit::systemTick, MICROBIT_DISPLAY_REFRESH_PERIOD);
 

source/MicroBitSuperMain.cpp

@@ -46,9 +46,12 @@ int main()
 
         if (i == 10)
         {
-            // Bring up the BLE stack if it isn't alredy done.
+            // Start the BLE stack, if it isn't already running.
             if (!uBit.ble)
-                uBit.bleManager.init(uBit.getName(), uBit.getSerial());
+            {
+                uBit.bleManager.init(uBit.getName(), uBit.getSerial(), true);
+                uBit.ble = uBit.bleManager.ble;
+            }
 
             // Enter pairing mode, using the LED matrix for any necessary pairing operations
             uBit.bleManager.pairingMode(uBit.display);
@@ -56,6 +59,15 @@ int main()
     }
 #endif
 
+#if CONFIG_ENABLED(MICROBIT_BLE_ENABLED)
+    // Start the BLE stack, if it isn't already running.
+    if (!uBit.ble)
+    {
+        uBit.bleManager.init(uBit.getName(), uBit.getSerial(), false);
+        uBit.ble = uBit.bleManager.ble;
+    }
+#endif
+
     app_main();
 
     // If app_main exits, there may still be other fibers running, registered event handlers etc.

source/ble-services/MicroBitBLEManager.cpp

@@ -127,7 +127,7 @@ void MicroBitBLEManager::advertise()
   * uBit.init();
   * @endcode
   */
-void MicroBitBLEManager::init(ManagedString deviceName, ManagedString serialNumber)
+void MicroBitBLEManager::init(ManagedString deviceName, ManagedString serialNumber, bool enableBonding)
 {
 	ManagedString BLEName("BBC micro:bit");
 
@@ -156,7 +156,7 @@ void MicroBitBLEManager::init(ManagedString deviceName, ManagedString serialNumb
     // Setup our security requirements.
     ble->securityManager().onPasskeyDisplay(passkeyDisplayCallback);
     ble->securityManager().onSecuritySetupCompleted(securitySetupCompletedCallback);
-    ble->securityManager().init(MICROBIT_BLE_ENABLE_BONDING, MICROBIT_BLE_REQUIRE_MITM, SecurityManager::IO_CAPS_DISPLAY_ONLY);
+    ble->securityManager().init(enableBonding, MICROBIT_BLE_REQUIRE_MITM, SecurityManager::IO_CAPS_DISPLAY_ONLY);
 
 #if CONFIG_ENABLED(MICROBIT_BLE_WHITELIST)
     // Configure a whitelist to filter all connection requetss from unbonded devices.