diff --git a/libraries/MySensors/drivers/ATSHA204/ATSHA204.cpp b/libraries/MySensors/drivers/ATSHA204/ATSHA204.cpp
index a38c5ec..3e16cc3 100644
--- a/libraries/MySensors/drivers/ATSHA204/ATSHA204.cpp
+++ b/libraries/MySensors/drivers/ATSHA204/ATSHA204.cpp
@@ -42,12 +42,12 @@ void ATSHA204Class::getSerialNumber(uint8_t * response)
 
 void ATSHA204Class::swi_set_signal_pin(uint8_t is_high)
 {
-  pinMode(device_pin, OUTPUT);
+  SHA204_SET_OUTPUT();
 
   if (is_high)
-	digitalWrite(device_pin, HIGH);
+	SHA204_POUT_HIGH();
   else
-	digitalWrite(device_pin, LOW);
+	SHA204_POUT_LOW();
 }
 
 uint8_t ATSHA204Class::swi_send_bytes(uint8_t count, uint8_t *buffer)
@@ -58,8 +58,9 @@ uint8_t ATSHA204Class::swi_send_bytes(uint8_t count, uint8_t *buffer)
   noInterrupts();  //swi_disable_interrupts();
 
   // Set signal pin as output.
-  pinMode(device_pin, OUTPUT);
-  digitalWrite(device_pin, HIGH);
+  SHA204_POUT_HIGH();
+  SHA204_SET_OUTPUT();
+  
 
   // Wait turn around time.
   delayMicroseconds(RX_TX_DELAY);  //RX_TX_DELAY;
@@ -70,21 +71,21 @@ uint8_t ATSHA204Class::swi_send_bytes(uint8_t count, uint8_t *buffer)
     {
       if (bit_mask & buffer[i]) 
       {
-        digitalWrite(device_pin, LOW); //*device_port_OUT &= ~device_pin;
+        SHA204_POUT_LOW() //*device_port_OUT &= ~device_pin;
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        digitalWrite(device_pin, HIGH); //*device_port_OUT |= device_pin;
+        SHA204_POUT_HIGH() //*device_port_OUT |= device_pin;
         delayMicroseconds(7*BIT_DELAY);  //BIT_DELAY_7;
       }
       else 
       {
         // Send a zero bit.
-        digitalWrite(device_pin, LOW); //*device_port_OUT &= ~device_pin;
+        SHA204_POUT_LOW() //*device_port_OUT &= ~device_pin;
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        digitalWrite(device_pin, HIGH); //*device_port_OUT |= device_pin;
+        SHA204_POUT_HIGH() //*device_port_OUT |= device_pin;
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        digitalWrite(device_pin, LOW); //*device_port_OUT &= ~device_pin;
+        SHA204_POUT_LOW() //*device_port_OUT &= ~device_pin;
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        digitalWrite(device_pin, HIGH); //*device_port_OUT |= device_pin;
+        SHA204_POUT_HIGH() //*device_port_OUT |= device_pin;
         delayMicroseconds(5*BIT_DELAY);  //BIT_DELAY_5;
       }
     }
@@ -110,8 +111,8 @@ uint8_t ATSHA204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
   noInterrupts(); //swi_disable_interrupts();
 
   // Configure signal pin as input.
-  pinMode(device_pin, INPUT);
-
+  SHA204_SET_INPUT();
+	
   // Receive bits and store in buffer.
   for (i = 0; i < count; i++)
   {
@@ -128,7 +129,7 @@ uint8_t ATSHA204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       while (--timeout_count > 0) 
       {
         // Wait for falling edge.
-        if (digitalRead(device_pin) == 0)
+        if (SHA204_PIN_READ() == 0)
           break;
       }
 
@@ -141,7 +142,7 @@ uint8_t ATSHA204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       do 
       {
         // Wait for rising edge.
-        if (digitalRead(device_pin) != 0) 
+        if (SHA204_PIN_READ() != 0) 
         {
           // For an Atmel microcontroller this might be faster than "pulse_count++".
           pulse_count = 1;
@@ -164,7 +165,7 @@ uint8_t ATSHA204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       // Detect possible edge indicating zero bit.
       do 
       {
-        if (digitalRead(device_pin) == 0) 
+        if (SHA204_PIN_READ() == 0) 
         {
           // For an Atmel microcontroller this might be faster than "pulse_count++".
           pulse_count = 2;
@@ -178,7 +179,7 @@ uint8_t ATSHA204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       {
         do 
         {
-          if (digitalRead(device_pin) != 0)
+          if (SHA204_PIN_READ() != 0)
             break;
         } while (timeout_count-- > 0);
       }
diff --git a/libraries/MySensors/drivers/ATSHA204/ATSHA204.h b/libraries/MySensors/drivers/ATSHA204/ATSHA204.h
index 0c18849..7569e21 100644
--- a/libraries/MySensors/drivers/ATSHA204/ATSHA204.h
+++ b/libraries/MySensors/drivers/ATSHA204/ATSHA204.h
@@ -220,6 +220,22 @@
 
 #define SHA204_SERIAL_SZ    9   // The number of bytes the serial number consists of
 
+/* Low level HW access macros */
+/* function calls is not working, as it will have too much overhead */
+#if !defined(ARDUINO_ARCH_AVR) // For everything else than AVR use pinMode / digitalWrite
+#define SHA204_SET_OUTPUT() pinMode(device_pin, OUTPUT)
+#define SHA204_SET_INPUT() pinMode(device_pin, INPUT)
+#define SHA204_POUT_HIGH() digitalWrite(device_pin, HIGH)
+#define SHA204_POUT_LOW() digitalWrite(device_pin, LOW)
+#define SHA204_PIN_READ() digitalRead(device_pin)
+#else
+#define SHA204_SET_INPUT()  *device_port_DDR &= ~device_pin
+#define SHA204_SET_OUTPUT() *device_port_DDR |= device_pin
+#define SHA204_POUT_HIGH() *device_port_OUT |= device_pin
+#define SHA204_POUT_LOW() *device_port_OUT &= ~device_pin
+#define SHA204_PIN_READ() (*device_port_IN & device_pin)
+#endif
+
 class ATSHA204Class
 {
 private:
diff --git a/libraries/sha204/sha204_library.cpp b/libraries/sha204/sha204_library.cpp
index 079524f..a747c4d 100644
--- a/libraries/sha204/sha204_library.cpp
+++ b/libraries/sha204/sha204_library.cpp
@@ -89,10 +89,10 @@ void atsha204Class::swi_set_signal_pin(uint8_t is_high)
 {
   SHA204_SET_OUTPUT();
   if (is_high) {
-    SHA204_SET_HIGH();
+    SHA204_POUT_HIGH();
   }
   else {
-    SHA204_SET_LOW();
+    SHA204_POUT_LOW();
   }
 
 }
@@ -105,7 +105,7 @@ uint8_t atsha204Class::swi_send_bytes(uint8_t count, uint8_t *buffer)
   noInterrupts();  //swi_disable_interrupts();
 
   // Set signal pin as output.
-  SHA204_SET_HIGH();
+  SHA204_POUT_HIGH();
   SHA204_SET_OUTPUT();	
   // Wait turn around time.
   delayMicroseconds(RX_TX_DELAY);  //RX_TX_DELAY;
@@ -116,21 +116,21 @@ uint8_t atsha204Class::swi_send_bytes(uint8_t count, uint8_t *buffer)
     {
       if (bit_mask & buffer[i]) 
       {
-        SHA204_SET_LOW();
+        SHA204_POUT_LOW();
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        SHA204_SET_HIGH();
+        SHA204_POUT_HIGH();
         delayMicroseconds(7*BIT_DELAY);  //BIT_DELAY_7;
       }
       else 
       {
         // Send a zero bit.
-        SHA204_SET_LOW();
+        SHA204_POUT_LOW();
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        SHA204_SET_HIGH();
+        SHA204_POUT_HIGH();
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        SHA204_SET_LOW();
+        SHA204_POUT_LOW();
         delayMicroseconds(BIT_DELAY);  //BIT_DELAY_1;
-        SHA204_SET_HIGH();
+        SHA204_POUT_HIGH();
         delayMicroseconds(5*BIT_DELAY);  //BIT_DELAY_5;
       }
     }
@@ -174,7 +174,7 @@ uint8_t atsha204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       while (--timeout_count > 0) 
       {
         // Wait for falling edge.
-        if (SHA204_READ_PIN() == 0)
+        if (SHA204_PIN_READ() == 0)
           break;
       }
 
@@ -187,7 +187,7 @@ uint8_t atsha204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       do 
       {
         // Wait for rising edge.
-        if (SHA204_READ_PIN() != 0) 
+        if (SHA204_PIN_READ() != 0) 
         {
           // For an Atmel microcontroller this might be faster than "pulse_count++".
           pulse_count = 1;
@@ -210,7 +210,7 @@ uint8_t atsha204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       // Detect possible edge indicating zero bit.
       do 
       {
-        if (SHA204_READ_PIN() == 0) 
+        if (SHA204_PIN_READ() == 0) 
         {
           // For an Atmel microcontroller this might be faster than "pulse_count++".
           pulse_count = 2;
@@ -224,7 +224,7 @@ uint8_t atsha204Class::swi_receive_bytes(uint8_t count, uint8_t *buffer)
       {
         do 
         {
-          if (SHA204_READ_PIN() != 0)
+          if (SHA204_PIN_READ() != 0)
             break;
         } while (timeout_count-- > 0);
       }
diff --git a/libraries/sha204/sha204_library.h b/libraries/sha204/sha204_library.h
index 4079e42..fe12392 100644
--- a/libraries/sha204/sha204_library.h
+++ b/libraries/sha204/sha204_library.h
@@ -284,15 +284,15 @@
 #if !defined(ARDUINO_ARCH_AVR) // For everything else than AVR use pinMode / digitalWrite
 #define SHA204_SET_OUTPUT() pinMode(device_pin, OUTPUT)
 #define SHA204_SET_INPUT() pinMode(device_pin, INPUT)
-#define SHA204_SET_HIGH() digitalWrite(device_pin, HIGH)
-#define SHA204_SET_LOW() digitalWrite(device_pin, LOW)
-#define SHA204_READ_PIN() digitalRead(device_pin)
+#define SHA204_POUT_HIGH() digitalWrite(device_pin, HIGH)
+#define SHA204_POUT_LOW() digitalWrite(device_pin, LOW)
+#define SHA204_PIN_READ() digitalRead(device_pin)
 #else
 #define SHA204_SET_INPUT()  *device_port_DDR &= ~device_pin
 #define SHA204_SET_OUTPUT() *device_port_DDR |= device_pin
-#define SHA204_SET_HIGH() *device_port_OUT |= device_pin
-#define SHA204_SET_LOW() *device_port_OUT &= ~device_pin
-#define SHA204_READ_PIN() (*device_port_IN & device_pin)
+#define SHA204_POUT_HIGH() *device_port_OUT |= device_pin
+#define SHA204_POUT_LOW() *device_port_OUT &= ~device_pin
+#define SHA204_PIN_READ() (*device_port_IN & device_pin)
 #endif
 
 class atsha204Class