Edwin the variable that you commented for Cmake is currenly not implmeted Errors were generated due to the missing IFDEF __CPP__ wrappers on the .h Files

CMakeLists.txt

@@ -33,7 +33,7 @@ add_subdirectory(utils)
 add_subdirectory(bsl)
 
 #set(BSL_HEADER_FILE ${CMAKE_SOURCE_DIR}/bsl/raspberry/bsl_raspberry.hpp)
-set(BSL_HEADER_FILE ${CMAKE_SOURCE_DIR}/bsl/nucleo_f042k6/bsl_nucleo_f042k6.hpp)
+#set(BSL_HEADER_FILE ${CMAKE_SOURCE_DIR}/bsl/nucleo_f042k6/bsl_nucleo_f042k6.hpp)
 
 message("${BoldBlue}Project Info  ${ColourReset}")
 message("${Blue} |--> Exec Name	\t: ${EXECUTABLE} ${ColourReset}")

bsl/csl/interfaces/timer.h

@@ -15,6 +15,13 @@
 **************************************************************************************************
 */
 
+#ifndef _TIMER_H_
+#define _TIMER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "hardwareDescription.h"
 
 typedef enum {
@@ -58,3 +65,8 @@ uint32_t timerGetCount(timerNo_t timer);
 
 void timerThrowError(timerError_t error); 
 
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _TIMER_H_

bsl/csl/stm32f042/Device/hardwareDescription.h

@@ -16,7 +16,15 @@
 **************************************************************************************************
 */
 
+#ifndef _hardwareDescription_H_
+#define _hardwareDescription_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "stm32f042x6.h"
+#include <stdint.h>
 
 #define PACKAGE_LQFP32 1
 
@@ -154,11 +162,12 @@ typedef enum {
 /*! 
  * Enum for awailable clok sources RM Page: 95 
  * */
+
 typedef enum { 
-	HSI,	/*!< High speed internal */ 
-	HSE,	/*!< High speed external */
-	LSI,	/*!< Low speed internal */
-	LSE		/*!< Low speed External */
+	CLK_HSI,	/*!< High speed internal */ 
+	CLK_HSE,	/*!< High speed external */
+	CLK_LSI,	/*!< Low speed internal */
+	CLK_LSE		/*!< Low speed External */
 }clkSources_t;
 
 /*!
@@ -193,3 +202,9 @@ static const uint8_t timerBus_No[MAX_TIMER_CHANNEL_COUNT] = {
 	2,
 	2
 };
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _hardwareDescription_H_

bsl/csl/stm32f042/Src/timer.c

@@ -51,7 +51,6 @@ void timerSetAutoReload(timerNo_t timer, uint32_t reload)
  
 void timerClearCounter(timerNo_t timer)
 {
-	
 	BASE->CNT = 0; 	
 }
  

bsl/csl/stm32f042/Src/usart.c

@@ -22,7 +22,6 @@
 
 #include "usart.h"
 #include "pin.h"
-#include "stm32f042x6.h"
 
 
 #define SYST_CLK 8000000

bsl/nucleo_f042k6/bslConfig.cmake

@@ -76,5 +76,5 @@ list(APPEND EXTRA_LIBS sub::translator)
 list(APPEND EXTRA_LIBS sub::delay)
 list(APPEND EXTRA_LIBS sub::pin) 
 list(APPEND EXTRA_LIBS sub::usart)
-list(APPEND EXTRA_LIBS sub::init)
 list(APPEND EXTRA_LIBS sub::timer)
+list(APPEND EXTRA_LIBS sub::init)