diff --git a/include/sta/hal/uart.hpp b/include/sta/hal/uart.hpp
index b9dd65e..e8e5434 100644
--- a/include/sta/hal/uart.hpp
+++ b/include/sta/hal/uart.hpp
@@ -1,10 +1,10 @@
 /**
- * @brief Implementation for UART using HAL.
+ * @brief Implementation of UART using HAL.
  *
- * Define STA_HAL_UART_ENABLE in <sta/config.hpp> to enable.
+ * Define **STA_HAL_UART_ENABLE** in `<sta/config.hpp>` to enable module.
  *
- * To enable the global DebugSerial instance (example using UART1) define:
- *   #define STA_HAL_UART_DEBUG huart1
+ * To use a HAL UART instance (e.g. UART1) for `<sta/debug_serial.hpp>` define:
+ *   #define STA_HAL_UART_DEBUG_SERIAL huart1
  */
 #ifndef STA_HAL_UART_HPP
 #define STA_HAL_UART_HPP
@@ -37,14 +37,6 @@ namespace sta
 	private:
 		UART_HandleTypeDef * handle_;   /**< UART handle */
 	};
-
-
-#ifdef STA_HAL_UART_DEBUG
-	/**
-	 * @brief Global UART instance for debug output.
-	 */
-	extern HalUART DebugSerial;
-#endif // STA_HAL_UART_DEBUG
 } // namespace sta
 
 
diff --git a/src/hal/uart.cpp b/src/hal/uart.cpp
index 9413a28..7d3fcc6 100644
--- a/src/hal/uart.cpp
+++ b/src/hal/uart.cpp
@@ -17,16 +17,22 @@ namespace sta
 } // namespace sta
 
 
-#ifdef STA_HAL_UART_DEBUG
+#ifdef STA_HAL_UART_DEBUG_SERIAL
+
+// Get extern declaration for DebugSerial because const namespace level variables have internal linkage by default
+#include <sta/debug_serial.hpp>
 
 #include <usart.h>
 
 namespace sta
 {
-	HalUART DebugSerial(&STA_HAL_UART_DEBUG);
+	HalUART gHalDebugSerial(&STA_HAL_UART_DEBUG_SERIAL);
+
+	// Used by <sta/debug.hpp>
+	UART * const DebugSerial = &gHalDebugSerial;
 } // namespace sta
 
-#endif // STA_HAL_UART_DEBUG
+#endif // STA_HAL_UART_DEBUG_SERIAL
 
 
 #endif // STA_HAL_UART_ENABLE