diff --git a/src/BlinkTask.h b/src/BlinkTask.h
index 5da32c2..8916d9e 100644
--- a/src/BlinkTask.h
+++ b/src/BlinkTask.h
@@ -111,10 +111,10 @@ class BlinkTask : public Task
 
     byte _outPin;
     uint8_t _bitMask;
-#ifndef ESP8266
-    volatile uint8_t *_portRegister;
-#else
+#if defined(ESP8266) || defined(ARDUINO_ARCH_SAMD)
     volatile uint32_t *_portRegister;
+#else
+    volatile uint8_t *_portRegister;
 #endif
 };
 
diff --git a/src/FrequencyTask.h b/src/FrequencyTask.h
index fe83d16..b383b49 100644
--- a/src/FrequencyTask.h
+++ b/src/FrequencyTask.h
@@ -53,10 +53,10 @@ class FrequencyTask : public Task
     int _outPin;
     boolean _stateOn;
     uint8_t _bitMask;
-#ifndef ESP8266
-    volatile uint8_t *_portRegister;
-#else
+#if defined(ESP8266) || defined(ARDUINO_ARCH_SAMD)
     volatile uint32_t *_portRegister;
+#else
+    volatile uint8_t *_portRegister;
 #endif
     static void step(Task* me);
 };
diff --git a/src/SoftPwmTask.h b/src/SoftPwmTask.h
index b50859f..5d93ef2 100644
--- a/src/SoftPwmTask.h
+++ b/src/SoftPwmTask.h
@@ -68,10 +68,10 @@ class SoftPwmTask : public Task
     static void step(Task* me);
     
     uint8_t _bitMask;
-#ifndef ESP8266
-    volatile uint8_t *_portRegister;
-#else
+#if defined(ESP8266) || defined(ARDUINO_ARCH_SAMD)
     volatile uint32_t *_portRegister;
+#else
+    volatile uint8_t *_portRegister;
 #endif
 };