diff --git a/bsl/csl/interfaces/pin.h b/bsl/csl/interfaces/pin.h
index 0aa8109..d1761d3 100644
--- a/bsl/csl/interfaces/pin.h
+++ b/bsl/csl/interfaces/pin.h
@@ -13,34 +13,35 @@ extern "C" {
 #include "../stm32f042/Drivers/CMSIS/Device/ST/STM32F0xx/Include/stm32f042x6.h"
 	typedef enum 
 	{
-		pinA0 = GPIOA_BASE	| 0,
-		pinA1 = GPIOA_BASE	| 1,
-		pinA2 = GPIOA_BASE	| 2,
-		pinA3 = GPIOA_BASE	| 3,
-		pinA4 = GPIOA_BASE	| 4,
-		pinA5 = GPIOA_BASE	| 5,
-		pinA6 = GPIOA_BASE	| 6,
-		pinA7 = GPIOA_BASE	| 7,
-		pinA8 = GPIOA_BASE	| 8,
-		pinA9 = GPIOA_BASE	| 9,
-		pinA10 = GPIOA_BASE | 10,
-		pinA11 = GPIOA_BASE | 11,
-		pinA12 = GPIOA_BASE | 12,
-		pinA13 = GPIOA_BASE | 13,
-		pinA14 = GPIOA_BASE | 14,
-		pinA15 = GPIOA_BASE | 15,
-
-		pinB0 = GPIOB_BASE	| 0,
-		pinB1 = GPIOB_BASE	| 1,
-		pinB3 = GPIOB_BASE	| 3,
-		pinB4 = GPIOB_BASE	| 4,
-		pinB5 = GPIOB_BASE	| 5,
-		pinB6 = GPIOB_BASE	| 6,
-		pinB7 = GPIOB_BASE	| 7,
-		pinB8 = GPIOB_BASE	| 8,
-
-		pinF0 = GPIOF_BASE	| 0,
-		pinF1 = GPIOF_BASE	| 1
+	//	NAME  = BASE ADDR   | PORT | PIN NO
+		pinA0 = GPIOA_BASE  | 0x00 | 0,
+		pinA1 = GPIOA_BASE	| 0x00 | 1,
+		pinA2 = GPIOA_BASE	| 0x00 | 2,
+		pinA3 = GPIOA_BASE	| 0x00 | 3,
+		pinA4 = GPIOA_BASE	| 0x00 | 4,
+		pinA5 = GPIOA_BASE	| 0x00 | 5,
+		pinA6 = GPIOA_BASE	| 0x00 | 6,
+		pinA7 = GPIOA_BASE	| 0x00 | 7,
+		pinA8 = GPIOA_BASE	| 0x00 | 8,
+		pinA9 = GPIOA_BASE	| 0x00 | 9,
+		pinA10 = GPIOA_BASE | 0x00 | 10,
+		pinA11 = GPIOA_BASE | 0x00 | 11,
+		pinA12 = GPIOA_BASE | 0x00 | 12,
+		pinA13 = GPIOA_BASE | 0x00 | 13,
+		pinA14 = GPIOA_BASE | 0x00 | 14,
+		pinA15 = GPIOA_BASE | 0x00 | 15,
+
+		pinB0 = GPIOB_BASE	| 0x10 | 0,
+		pinB1 = GPIOB_BASE	| 0x10 | 1,
+		pinB3 = GPIOB_BASE	| 0x10 | 3,
+		pinB4 = GPIOB_BASE	| 0x10 | 4,
+		pinB5 = GPIOB_BASE	| 0x10 | 5,
+		pinB6 = GPIOB_BASE	| 0x10 | 6,
+		pinB7 = GPIOB_BASE	| 0x10 | 7,
+		pinB8 = GPIOB_BASE	| 0x10 | 8,
+
+		pinF0 = GPIOF_BASE	| 0x20 | 0,
+		pinF1 = GPIOF_BASE	| 0x20 | 1
 	}pinNo_t;
 #endif
 
diff --git a/bsl/csl/stm32f042/Src/pin.c b/bsl/csl/stm32f042/Src/pin.c
index f6e9d7b..33a2d21 100644
--- a/bsl/csl/stm32f042/Src/pin.c
+++ b/bsl/csl/stm32f042/Src/pin.c
@@ -13,7 +13,9 @@
 #define PUPDR_PULL_UP	0x1UL
 #define PUPDR_PULL_DOWN	0x2UL
 
-const uint32_t moderMode[4] = {
+#define PIN_BASE ((GPIO_TypeDef *)(pinNo&~0xFF))
+
+const uint32_t moderMode[5] = {
 	MODER_ANALOG, 
 	MODER_IN,
 	MODER_OUT, 
@@ -21,23 +23,36 @@ const uint32_t moderMode[4] = {
 	MODER_ALTERNATE
 };
 
+const uint32_t pinPort[3] = {
+	RCC_AHBENR_GPIOAEN, 
+	RCC_AHBENR_GPIOBEN, 
+	RCC_AHBENR_GPIOFEN 
+};
+
+const uint32_t pinPullUpDown[3] = {
+	PUPDR_NO_PULL,
+	PUPDR_PULL_UP,
+	PUPDR_PULL_DOWN
+};
+
 void setMode(pinNo_t pinNo, mode mode)
 {
 	init(pinNo);
 	//Clear entry.
-	((GPIO_TypeDef *)(pinNo&~0xFF))->MODER &=~ (MODER_ANALOG << ((pinNo & 0xFF) * 2));
+	PIN_BASE->MODER &=~ (0x3 << ((pinNo & 0x0F) * 2));
 	//Set to corresponding mode.
-	((GPIO_TypeDef *)(pinNo&~0xFF))->MODER |= (moderMode[mode] << ((pinNo & 0xFF) * 2));
+	PIN_BASE->MODER |= (moderMode[mode] << ((pinNo & 0x0F) * 2));
 }
 
 void setOutputState(pinNo_t pinNo, state state)
 {
-
+	
 }
  
 void setPullUpDonw(pinNo_t pinNo, pullUpDown resistance)
 {
-	
+    PIN_BASE->PUPDR &= ~(0x3 << ((pinNo & 0x0F) * 2));
+    PIN_BASE->PUPDR |= (pinPullUpDown[resistance] << ((pinNo & 0x0F) * 2));
 }
  
 void setSpeed(pinNo_t pinNo, speed speed)
@@ -63,18 +78,17 @@ void toggle(pinNo_t pinNo)
 
 void set(pinNo_t pinNo, uint8_t state)
 {
-	if(state == 1)
-	{
-		GPIOB->BSRR |= GPIO_BSRR_BS_3; 
+	if(state) {
+		PIN_BASE->BSRR |= (GPIO_BSRR_BS_0 << ((pinNo & 0xF)));
 		return;
 	}
-	GPIOB->BSRR |= GPIO_BSRR_BR_3;
+		PIN_BASE->BSRR |= (GPIO_BSRR_BR_0 << ((pinNo & 0xF)));
 }
 
 //Enable the pin port's clock
 void init(pinNo_t pinNo)
 {
-	RCC->AHBENR |= RCC_AHBENR_GPIOBEN;
+	RCC->AHBENR |= pinPort[((pinNo & 0xF0)>>4)];
 }
 
 void deInit(pinNo_t pinNo)