diff --git a/src/RS485.cpp b/src/RS485.cpp
index 5c8842d..c70a799 100644
--- a/src/RS485.cpp
+++ b/src/RS485.cpp
@@ -21,7 +21,7 @@
 
 #ifdef __MBED__
 #include "pinDefinitions.h"
-RS485Class::RS485Class(HardwareSerial& hwSerial, PinName txPin, PinName dePin, PinName rePin) :
+RS485Class::RS485Class(SERIAL_HARDWARE_CLASS& hwSerial, PinName txPin, PinName dePin, PinName rePin) :
   _serial(&hwSerial),
   _txPin(PinNameToIndex(txPin)),
   _dePin(PinNameToIndex(dePin)),
@@ -31,7 +31,7 @@ RS485Class::RS485Class(HardwareSerial& hwSerial, PinName txPin, PinName dePin, P
 }
 #endif
 
-RS485Class::RS485Class(HardwareSerial& hwSerial, int txPin, int dePin, int rePin) :
+RS485Class::RS485Class(SERIAL_HARDWARE_CLASS& hwSerial, int txPin, int dePin, int rePin) :
   _serial(&hwSerial),
   _txPin(txPin),
   _dePin(dePin),
@@ -50,12 +50,12 @@ void RS485Class::begin(unsigned long baudrate, int predelay, int postdelay)
   begin(baudrate, SERIAL_8N1, predelay, postdelay);
 }
 
-void RS485Class::begin(unsigned long baudrate, uint16_t config)
+void RS485Class::begin(unsigned long baudrate, SERIAL_MODE_TYPE config)
 {
   begin(baudrate, config, RS485_DEFAULT_PRE_DELAY, RS485_DEFAULT_POST_DELAY);
 }
 
-void RS485Class::begin(unsigned long baudrate, uint16_t config, int predelay, int postdelay)
+void RS485Class::begin(unsigned long baudrate, SERIAL_MODE_TYPE config, int predelay, int postdelay)
 {
   _baudrate = baudrate;
   _config = config;
@@ -206,5 +206,5 @@ void RS485Class::setDelays(int predelay, int postdelay)
 #ifdef RS485_SERIAL_PORT
 RS485Class RS485(RS485_SERIAL_PORT, RS485_DEFAULT_TX_PIN, RS485_DEFAULT_DE_PIN, RS485_DEFAULT_RE_PIN);
 #else
-RS485Class RS485(SERIAL_PORT_HARDWARE, RS485_DEFAULT_TX_PIN, RS485_DEFAULT_DE_PIN, RS485_DEFAULT_RE_PIN);
+RS485Class RS485(SERIAL_PORT_HARDWARE_DEFAULT, RS485_DEFAULT_TX_PIN, RS485_DEFAULT_DE_PIN, RS485_DEFAULT_RE_PIN);
 #endif
diff --git a/src/RS485.h b/src/RS485.h
index 787d66c..dfd1038 100644
--- a/src/RS485.h
+++ b/src/RS485.h
@@ -22,6 +22,18 @@
 
 #include <Arduino.h>
 
+#ifdef ARDUINO_SAM_DUE
+#define SERIAL_HARDWARE_CLASS USARTClass
+#define SERIAL_MODE_TYPE UARTClass::UARTModes
+#else
+#define SERIAL_HARDWARE_CLASS HardwareSerial
+#define SERIAL_MODE_TYPE uint16_t
+#endif
+
+#ifdef ARDUINO_ARCH_SAM
+#define PIN_SERIAL1_TX 18
+#endif
+
 #ifndef RS485_DEFAULT_TX_PIN
 #ifdef PIN_SERIAL1_TX
 #define RS485_DEFAULT_TX_PIN PIN_SERIAL1_TX
@@ -40,9 +52,13 @@
 #define RS485_DEFAULT_DE_PIN A4
 #define RS485_DEFAULT_RE_PIN A5
 #elif defined(ARDUINO_UNOR4_WIFI) || defined(ARDUINO_UNOR4_MINIMA)
-#define SERIAL_PORT_HARDWARE Serial1
+#define SERIAL_PORT_HARDWARE_DEFAULT Serial1
 #define RS485_DEFAULT_DE_PIN 8
 #define RS485_DEFAULT_RE_PIN 7
+#elif  defined(ARDUINO_ARCH_SAM)
+#define SERIAL_PORT_HARDWARE_DEFAULT Serial1
+#define RS485_DEFAULT_DE_PIN 23
+#define RS485_DEFAULT_RE_PIN -1
 #else
 #ifndef RS485_DEFAULT_DE_PIN
 #define RS485_DEFAULT_DE_PIN A6
@@ -50,6 +66,10 @@
 #endif
 #endif
 
+#ifndef SERIAL_PORT_HARDWARE_DEFAULT
+#define SERIAL_PORT_HARDWARE_DEFAULT SERIAL_PORT_HARDWARE
+#endif
+
 #ifdef CUSTOM_RS485_DEFAULT_DE_PIN
 # define RS485_DEFAULT_DE_PIN CUSTOM_RS485_DEFAULT_DE_PIN
 #endif
@@ -64,14 +84,14 @@
 class RS485Class : public Stream {
   public:
 #ifdef __MBED__
-    RS485Class(HardwareSerial& hwSerial, PinName txPin, PinName dePin, PinName rePin);
+    RS485Class(SERIAL_HARDWARE_CLASS& hwSerial, PinName txPin, PinName dePin, PinName rePin);
 #endif
-    RS485Class(HardwareSerial& hwSerial, int txPin, int dePin, int rePin);
+    RS485Class(SERIAL_HARDWARE_CLASS& hwSerial, int txPin, int dePin, int rePin);
 
     virtual void begin(unsigned long baudrate);
-    virtual void begin(unsigned long baudrate, uint16_t config);
     virtual void begin(unsigned long baudrate, int predelay, int postdelay);
-    virtual void begin(unsigned long baudrate, uint16_t config, int predelay, int postdelay);
+    virtual void begin(unsigned long baudrate, SERIAL_MODE_TYPE config);
+    virtual void begin(unsigned long baudrate, SERIAL_MODE_TYPE config, int predelay, int postdelay);
     virtual void end();
     virtual int available();
     virtual int peek();
@@ -94,7 +114,7 @@ class RS485Class : public Stream {
     void setDelays(int predelay, int postdelay);
 
   private:
-    HardwareSerial* _serial;
+    SERIAL_HARDWARE_CLASS* _serial;
     int _txPin;
     int _dePin;
     int _rePin;
@@ -103,9 +123,9 @@ class RS485Class : public Stream {
 
     bool _transmisionBegun;
     unsigned long _baudrate;
-    uint16_t _config;
+    SERIAL_MODE_TYPE _config;
 };
 
 extern RS485Class RS485;
 
-#endif
+#endif
\ No newline at end of file