add bus off recovery

lib/nmea2ktwai/Nmea2kTwai.h

@@ -6,6 +6,15 @@
 class Nmea2kTwai : public tNMEA2000{
     public:
         Nmea2kTwai(gpio_num_t _TxPin,  gpio_num_t _RxPin,GwLog *logger);
+        typedef enum{
+            ST_STOPPED,
+            ST_RUNNING,
+            ST_BUS_OFF,
+            ST_RECOVERING,
+            ST_ERROR
+        } STATE;
+        STATE getState();
+        bool startRecovery();
     protected:
     // Virtual functions for different interfaces. Currently there are own classes
     // for Arduino due internal CAN (NMEA2000_due), external MCP2515 SPI CAN bus controller (NMEA2000_mcp),
@@ -17,6 +26,8 @@ class Nmea2kTwai : public tNMEA2000{
     // and you want to change size of library send frame buffer size. See e.g. NMEA2000_teensy.cpp.
     virtual void InitCANFrameBuffers();
 
+    
+
     private:
     gpio_num_t TxPin;  
     gpio_num_t RxPin;