* companion radio for RAK (USB) now fixed. (thanks to Bernd Giesecke)

* experimental NRF52 impl of SerialBLEInterface, and experimental RAK BLE companion radio target

src/helpers/nrf52/SerialBLEInterface.h

@@ -0,0 +1,58 @@
+#pragma once
+
+#include "../BaseSerialInterface.h"
+#include <bluefruit.h>
+
+class SerialBLEInterface : public BaseSerialInterface {
+  BLEUart bleuart;
+  bool deviceConnected;
+  bool oldDeviceConnected;
+  bool checkAdvRestart;
+  bool _isEnabled;
+  uint32_t _pin_code;
+  unsigned long _last_write;
+
+  struct Frame {
+    uint8_t len;
+    uint8_t buf[MAX_FRAME_SIZE];
+  };
+
+  #define FRAME_QUEUE_SIZE  4
+  int send_queue_len;
+  Frame send_queue[FRAME_QUEUE_SIZE];
+
+  void clearBuffers() { send_queue_len = 0; }
+  void startAdv();
+
+public:
+  SerialBLEInterface() {
+    deviceConnected = false;
+    oldDeviceConnected = false;
+    checkAdvRestart = false;
+    _isEnabled = false;
+    _last_write = 0;
+    send_queue_len = 0;
+  }
+
+  void begin(const char* device_name, uint32_t pin_code);
+
+  // BaseSerialInterface methods
+  void enable() override;
+  void disable() override;
+  bool isEnabled() const override { return _isEnabled; }
+
+  bool isConnected() const override;
+
+  bool isWriteBusy() const override;
+  size_t writeFrame(const uint8_t src[], size_t len) override;
+  size_t checkRecvFrame(uint8_t dest[]) override;
+};
+
+#if BLE_DEBUG_LOGGING && ARDUINO
+  #include <Arduino.h>
+  #define BLE_DEBUG_PRINT(F, ...) Serial.printf("BLE: " F, ##__VA_ARGS__)
+  #define BLE_DEBUG_PRINTLN(F, ...) Serial.printf("BLE: " F "\n", ##__VA_ARGS__)
+#else
+  #define BLE_DEBUG_PRINT(...) {}
+  #define BLE_DEBUG_PRINTLN(...) {}
+#endif