diff --git a/bsl/csl/interfaces/pin.h b/bsl/csl/interfaces/pin.h
index 883ac67..f69b0fe 100644
--- a/bsl/csl/interfaces/pin.h
+++ b/bsl/csl/interfaces/pin.h
@@ -73,7 +73,7 @@ extern "C" {
 /*! Enum of possible Pin Modes */
 typedef enum 
 {
-	undefined,	/*!< Is the **default** mode */
+	def_mode,	/*!< Is the **default** mode */
 	input,		/*!< Set pin as **Input** */
 	output, 	/*!< Set pin as **Output** */
 	analog, 	/*!< Set pin as **Analog** */
@@ -83,14 +83,16 @@ typedef enum
 /*! Enum of possible Outpout Stages */
 typedef enum 
 {
-	floating, /*!< Set ouput stage to **Floating** */
-	pushPull, /*!< Set ouput stage to **Push Pull** */
-	openDrain /*!< Set ouput stage to **Open Drain** */
+	def_stage,	/*!< Set ouput stage to **Default** */
+	floating,	/*!< Set ouput stage to **Floating** */
+	pushPull,	/*!< Set ouput stage to **Push Pull** */
+	openDrain	/*!< Set ouput stage to **Open Drain** */
 }stage_t;
 
 /*! Enum for the internal Pull-Up/Down resistors */
 typedef enum 
 {
+	def_res,	/*!< **Default** internal resistance */
 	none,		/*!< **Disbales** internal resistance */
 	pullUp,		/*!< Set internal resistance as **Pull-Up** */
 	pullDown	/*!< Set internal resistance as **Pull-Down** */
@@ -99,6 +101,7 @@ typedef enum
 /*! Enum to set the pin's speed*/
 typedef enum 
 {
+	def_speed,	/*!< set pin's spped to **Default** */
 	slow,		/*!< set pin's speed to **Slow** */
 	normal,		/*!< set pin's speed to **Normal** */ 
 	fast,		/*!< set pin's speed to **Fast** */
diff --git a/bsl/csl/stm32f042/Src/pin.c b/bsl/csl/stm32f042/Src/pin.c
index 6db7392..295faa7 100644
--- a/bsl/csl/stm32f042/Src/pin.c
+++ b/bsl/csl/stm32f042/Src/pin.c
@@ -2,8 +2,8 @@
   **************************************************************************************************
   * @file		pin.c
   * @author		Kerem Yollu & Edwin Koch
-  * @date		02.11.2021
-  * @version	1.0
+  * @date		03.11.2021
+  * @version	1.01
   ************************************************************************************************** 
   * @brief		Implementation of pin.h for the STM32F042K6 MCU
   * 
@@ -62,7 +62,8 @@ const uint32_t pinPort[3] = {
 /**
 * Table for binding the Pin pullUpDown_t enum index to the values that the PUPDR register needs
 */
-const uint32_t pinPullUpDown[3] = {
+const uint32_t pinPullUpDown[4] = {
+	PUPDR_NO_PULL,
 	PUPDR_NO_PULL,
 	PUPDR_PULL_UP,
 	PUPDR_PULL_DOWN
@@ -71,7 +72,8 @@ const uint32_t pinPullUpDown[3] = {
 /**
 * Table for binding the Pin speed_t enum index to the values that the OSPEEDR register needs
 */
-const uint32_t speedList[4] = {
+const uint32_t speedList[5] = {
+	OSPEEDR_MEDIUM,
 	OSPEEDR_LOW,
 	OSPEEDR_LOW,
 	OSPEEDR_MEDIUM,
@@ -82,8 +84,9 @@ const uint32_t speedList[4] = {
 /**
 * Table for binding the Pin stage_t enum index to the values that the OTYPER register needs
 */
-const uint32_t outputStgeList[3] = 
+const uint32_t outputStgeList[4] = 
 {
+	OTYPER_PUSH_PULL,
 	OTYPER_OPEN_DRAIN,
 	OTYPER_PUSH_PULL,
 	OTYPER_OPEN_DRAIN
@@ -117,14 +120,14 @@ void pinSetSpeed(pinNo_t pinNo, speed_t speed)
  
 void pinSetAlternate(pinNo_t pinNo, uint16_t alternate)
 {
-	if(PIN_NO > 7)
+	if(PIN_NO < 7)
 	{
-		PIN_BASE->AFR[0] &= ~(0x0F << (PIN_NO * 2));
-		PIN_BASE->AFR[0] |= ((alternate & 0x0f) << (PIN_NO * 2));
+		PIN_BASE->AFR[0] &= ~(0x0F << (PIN_NO * 4));
+		PIN_BASE->AFR[0] |= ((alternate & 0x0F) << (PIN_NO * 4));
+		return; 
 	}
-
-	PIN_BASE->AFR[1] &= ~(0x0F << (PIN_NO * 2));
-	PIN_BASE->AFR[1] |= ((alternate & 0x0f) << (PIN_NO * 2));
+	PIN_BASE->AFR[1] &= ~(0x0F << (PIN_NO * 4));
+	PIN_BASE->AFR[1] |= ((alternate & 0x0F) << (PIN_NO * 4));
 }
 
 void pinConfig(pinNo_t pinNo, mode_t mode, stage_t stage, pullUpDown_t resistance, speed_t speed)
diff --git a/bsl/csl/stm32f042/Src/usart.c b/bsl/csl/stm32f042/Src/usart.c
index 6268845..2393455 100644
--- a/bsl/csl/stm32f042/Src/usart.c
+++ b/bsl/csl/stm32f042/Src/usart.c
@@ -1,8 +1,26 @@
+/**
+  **************************************************************************************************
+  * @file		usart.c
+  * @author		Kerem Yollu & Edwin Koch
+  * @date		03.11.2021
+  * @version	0.4 Unstable
+  ************************************************************************************************** 
+  * @brief		Implementation of usart.h for the STM32F042K6 MCU
+  * 
+  * **Detailed Description :**
+  * 
+  * This source code uses bit manipulation in order to minimise the footprint of pin initialisation 
+  * and manipulation. It's based on the CMSIS/Device/ST/STM32F0xx/Include/stm32f042x6.h Header file
+  * to get the obtain the right Registers. 
+  *
+  *
+  **************************************************************************************************
+*/
+
 #include"usart.h"
 #include"pin.h"
 
 
-
 #define USART2_EN (1U << 17)
 #define CR1_TE_EN (1U << 3)
 #define CR1_UE_EN (1U << 0)
@@ -11,26 +29,18 @@
 
 #define UART_BAUD 115200
 #define SYST_CLK 8000000
-
+#define AF1 0x01
 
 void usartSetBaudRate(uint32_t baud);
 
 void usartInit()
 {
 	/* COnfiguring teh pins for the uart*/ 
-	//pinConfig(pinA2, alternate, none, none, normal);
-	//pinConfig(pinA15, alternate, none, none, normal);
-	
+	pinConfig(pinA2, alternate, def_stage, def_res, def_speed);
+	pinConfig(pinA15, alternate, def_stage, def_res, def_speed);
+		
 	//Sets pina2 to alternate mode as UART_TX
-	//pinSetAlternate(pinA2, 1);
-	
-	GPIOA->MODER &= ~(1u <<4); 
-	GPIOA->MODER |= (1u <<5); 
-	
-	GPIOA->AFR[0] &= ~(1u<<11);
-	GPIOA->AFR[0] &= ~(1u<<10);
-	GPIOA->AFR[0] &= ~(1u<<9);
-	GPIOA->AFR[0] |= (1u<<8);
+	pinSetAlternate(pinA2, AF1);
 
 	//Enable the priferas bus and UART
 	RCC->APB1ENR |= USART2_EN; 	
@@ -38,8 +48,7 @@ void usartInit()
 	usartSetBaudRate(UART_BAUD);
 	
 	//enables the transmit and sets all the other values to 0 = Default 
-	USART2->CR1 = 0; // The = 0 is on purpose to set uart to default mode.    
-	USART2->CR1 |= CR1_TE_EN; // The = 0 is on purpose to set uart to default mode.    
+	USART2->CR1 = CR1_TE_EN; // The = 0 is on purpose to set uart to default mode.    
 	
 	//UART Enable
 	USART2->CR1 |= CR1_UE_EN; 	
@@ -47,12 +56,13 @@ void usartInit()
 
 static uint16_t usartComputeBaudRate(uint32_t clk, uint32_t baud)
 {
-	return((clk + (baud/2U))/baud);
+	//return((clk + (baud/2U))/baud);
+	return(clk/baud);
 }	
 
 void usartSetBaudRate(uint32_t baud)
 {
-	USART2->BRR = usartComputeBaudRate(baud, SYST_CLK); 
+	USART2->BRR = usartComputeBaudRate(SYST_CLK,baud); 
 }
 
 void usartSendChar(int ch)
diff --git a/main.cpp b/main.cpp
index c40ce22..65d575f 100644
--- a/main.cpp
+++ b/main.cpp
@@ -26,7 +26,6 @@ int main(int argc, char *argv[])
 
 	while(1)
 	{
-		
 		if(pinRead(pinA0))
 		{
 			pinWrite(pinB3,1);
@@ -35,7 +34,6 @@ int main(int argc, char *argv[])
 		{
 			pinWrite(pinB3,0);
 		}	
-
 	}
 	return 1;
 }