move instance data to protected - to support subclasses as needed

Author: gigapod

src/sfeTkArdI2C.h

@@ -138,7 +138,10 @@ class sfeTkArdI2C : public sfeTkII2C
     ///
     virtual int readRegisterRegion(uint8_t devReg, uint8_t *data, size_t numBytes);
 
-  private:
+  protected:
+    // note: The wire port is protected, allowing access if a sub-class is
+    //      created to implement a special read/write routine
+    //
     // The actual Arduino i2c port
     TwoWire *_i2cPort;
 };

src/sfeTkArdSPI.h

@@ -128,7 +128,11 @@ class sfeTkArdSPI : public sfeTkISPI
     ///
     virtual int readRegisterRegion(uint8_t reg, uint8_t *data, size_t numBytes);
 
-  private:
+  protected:
+    // note: The instance data is protected, allowing access if a sub-class is
+    //      created to implement a special read/write routine
+    //
+
     SPIClass *_spiPort;
 
     // Settings are used for every transaction.