Initial commit: Simple Sensor firmware for Heltec T114 with BME280

- MeshCore-based Simple Sensor firmware
- Heltec T114 without display
- BME280 sensor support (temp/humidity/pressure)
- Radio: 868.856018 MHz, SF7, BW62.5 kHz, CR4/7
- 2-byte path hash
- PlatformIO project

src/helpers/nrf52/SerialBLEInterface.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include "../BaseSerialInterface.h"
+#include <bluefruit.h>
+
+#ifndef BLE_TX_POWER
+#define BLE_TX_POWER 4
+#endif
+
+class SerialBLEInterface : public BaseSerialInterface {
+  BLEDfu bledfu;
+  BLEUart bleuart;
+  bool _isEnabled;
+  bool _isDeviceConnected;
+  uint16_t _conn_handle;
+  unsigned long _last_health_check;
+  unsigned long _last_retry_attempt;
+
+  struct Frame {
+    uint8_t len;
+    uint8_t buf[MAX_FRAME_SIZE];
+  };
+
+  #define FRAME_QUEUE_SIZE  12
+  
+  uint8_t send_queue_len;
+  Frame send_queue[FRAME_QUEUE_SIZE];
+  
+  uint8_t recv_queue_len;
+  Frame recv_queue[FRAME_QUEUE_SIZE];
+
+  void clearBuffers();
+  void shiftSendQueueLeft();
+  void shiftRecvQueueLeft();
+  bool isValidConnection(uint16_t handle, bool requireWaitingForSecurity = false) const;
+  bool isAdvertising() const;
+  static void onConnect(uint16_t connection_handle);
+  static void onDisconnect(uint16_t connection_handle, uint8_t reason);
+  static void onSecured(uint16_t connection_handle);
+  static bool onPairingPasskey(uint16_t connection_handle, uint8_t const passkey[6], bool match_request);
+  static void onPairingComplete(uint16_t connection_handle, uint8_t auth_status);
+  static void onBLEEvent(ble_evt_t* evt);
+  static void onBleUartRX(uint16_t conn_handle);
+
+public:
+  SerialBLEInterface() {
+    _isEnabled = false;
+    _isDeviceConnected = false;
+    _conn_handle = BLE_CONN_HANDLE_INVALID;
+    _last_health_check = 0;
+    _last_retry_attempt = 0;
+    send_queue_len = 0;
+    recv_queue_len = 0;
+  }
+
+  /**
+   * init the BLE interface.
+   * @param prefix   a prefix for the device name
+   * @param name  IN/OUT - a name for the device (combined with prefix). If "@@MAC", is modified and returned
+   * @param pin_code   the BLE security pin
+   */
+  void begin(const char* prefix, char* name, uint32_t pin_code);
+
+  void disconnect();
+  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