diff --git a/AS5600.cpp b/AS5600.cpp
index 33b03bd..13652e9 100644
--- a/AS5600.cpp
+++ b/AS5600.cpp
@@ -79,7 +79,7 @@ bool AS5600::begin(int dataPin, int clockPin, uint8_t directionPin)
 #endif
 
 
-#if defined (STM32)
+#if defined (ARDUINO_ARCH_STM32)
 
 bool AS5600::begin(int dataPin, int clockPin, uint8_t directionPin)
 {
diff --git a/AS5600.h b/AS5600.h
index 6bd4904..411e49f 100644
--- a/AS5600.h
+++ b/AS5600.h
@@ -89,7 +89,7 @@ class AS5600
 public:
   AS5600(TwoWire *wire = &Wire);
 
-#if defined (ESP8266) || defined(ESP32) || (STM32)
+#if defined (ESP8266) || defined(ESP32) || defined(ARDUINO_ARCH_STM32)
   //  AS5600_SW_DIRECTION_PIN is software controlled direction pin
   bool     begin(int dataPin, int clockPin, uint8_t directionPin = AS5600_SW_DIRECTION_PIN);
 #endif
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9d21768..11e0a1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
 ## [0.4.1] - 2023-09-16
-- fix #45 support STM32 set I2C pins
+- fix #45 support STM32 set I2C pins  ARDUINO_ARCH_STM32
 - update readme badges
 - minor edits
 
diff --git a/examples/AS5600_demo_radians/AS5600_demo_radians.ino b/examples/AS5600_demo_radians/AS5600_demo_radians.ino
index 7e8b281..3c7d363 100644
--- a/examples/AS5600_demo_radians/AS5600_demo_radians.ino
+++ b/examples/AS5600_demo_radians/AS5600_demo_radians.ino
@@ -19,6 +19,7 @@ void setup()
 
   Wire.begin();
 
+  //  as5600.begin(11, 12, 4);  //  test for STM32 or ESP32
   as5600.begin(4);  //  set direction pin.
   as5600.setDirection(AS5600_CLOCK_WISE);  // default, just be explicit.
 }