diff --git a/src/Arduino_PortentaBreakout.cpp b/src/Arduino_PortentaBreakout.cpp
new file mode 100644
index 0000000..8d5eb8b
--- /dev/null
+++ b/src/Arduino_PortentaBreakout.cpp
@@ -0,0 +1,3 @@
+#include "Arduino_PortentaBreakout.h"
+
+BreakoutCarrierClass Breakout;
diff --git a/src/Arduino_PortentaBreakout.h b/src/Arduino_PortentaBreakout.h
index 308eb8f..dc867c9 100644
--- a/src/Arduino_PortentaBreakout.h
+++ b/src/Arduino_PortentaBreakout.h
@@ -268,6 +268,6 @@ class BreakoutCarrierClass {
     }
 };
 
-BreakoutCarrierClass Breakout;
+extern BreakoutCarrierClass Breakout;
 
 #endif // ARDUINO_PORTENTA_BREAKOUT_H