diff --git a/doc/Assignment/Interrupt_assignment_observations.pdf b/doc/Assignment/Interrupt_assignment_observations.pdf
new file mode 100644
index 0000000..ce5a6da
Binary files /dev/null and b/doc/Assignment/Interrupt_assignment_observations.pdf differ
diff --git a/projects/lpc40xx_freertos/assignment_include.h b/projects/lpc40xx_freertos/assignment_include.h
new file mode 100644
index 0000000..9b20504
--- /dev/null
+++ b/projects/lpc40xx_freertos/assignment_include.h
@@ -0,0 +1,24 @@
+/**
+ * @file assignment_include.h
+ * @author Tejas Pidkalwar
+ * @date 19th Sept 2020
+ * @brief This file maintains the macro defined to enable specific assignment implementation for
+ *      execution, along with subparts of assignment enabling feature
+ */ 
+#ifndef _ASSIGNMENT_INCLUDE_
+#define _ASSIGNMENT_INCLUDE_
+
+/*
+ * This file defines macros corresponding each assignment.
+ * Enable only one assignment macro while compiling.
+ * This file also defines macros for sub parts corresponding to each assignment.
+ * Take care to enable only one part macro enabled while compiling.
+ */
+
+// Assignment 3
+#define INTERRUPT_ASSIGNMENT
+    //#define PART0_IRQ_ASSGNMT
+    //#define PART1_IRQ_ASSGNMT
+    #define PART2_IRQ_ASSGNMT
+
+#endif
\ No newline at end of file
diff --git a/projects/lpc40xx_freertos/interrupt_vector_table.c b/projects/lpc40xx_freertos/interrupt_vector_table.c
index a2f2e5a..87d252a 100644
--- a/projects/lpc40xx_freertos/interrupt_vector_table.c
+++ b/projects/lpc40xx_freertos/interrupt_vector_table.c
@@ -6,6 +6,10 @@
 #include "function_types.h"
 #include "lpc40xx.h"
 
+#ifdef PART0_IRQ_ASSGNMT
+extern void gpio_interrupt(void);
+#endif
+
 /**
  * _estack symbol is actually a pointer to the start of the stack memory (provided by the linker script).
  * Declaring as unsigned int to inform compiler that this symbol is constant and defined at link time.
@@ -93,7 +97,11 @@ __attribute__((section(".interrupt_vector_table"))) const function__void_f inter
     lpc_peripheral__interrupt_dispatcher, // 51 UART 4
     lpc_peripheral__interrupt_dispatcher, // 52 SSP 2
     lpc_peripheral__interrupt_dispatcher, // 53 LCD
+#ifdef PART0_IRQ_ASSGNMT
+    gpio_interrupt, // 54 GPIO Interrupt
+#else
     lpc_peripheral__interrupt_dispatcher, // 54 GPIO Interrupt
+#endif
     lpc_peripheral__interrupt_dispatcher, // 55 PWM 0
     lpc_peripheral__interrupt_dispatcher, // 56 EEPROM
 };
diff --git a/projects/lpc40xx_freertos/l3_drivers/gpio_isr.h b/projects/lpc40xx_freertos/l3_drivers/gpio_isr.h
new file mode 100644
index 0000000..d475746
--- /dev/null
+++ b/projects/lpc40xx_freertos/l3_drivers/gpio_isr.h
@@ -0,0 +1,40 @@
+/**
+ * @file gpio_isr.h
+ * @author Tejas Pidkalwar
+ * @date 20th Sept 2020
+ * @brief This file maintains the abstracted APIs to configure GPIO interrupts
+ */
+
+#pragma once
+
+#include "lpc40xx.h"
+#include <stdint.h>
+
+typedef enum {
+  GPIO_INTR__FALLING_EDGE,
+  GPIO_INTR__RISING_EDGE,
+} gpio_interrupt_e;
+
+// Function pointer type (demonstrated later in the code sample)
+typedef void (*function_pointer_t)(void);
+
+/**
+ * Allow the user to attach GPIO0 interrupt callback
+ * @param pin GPIO pin to be configured for GPIO interrupt
+ * @param interrupt_type Type of interrupt configuration
+ * @param callback An ISR function to be called on occurance of this interrupt
+ */
+void gpio0__attach_interrupt(uint32_t pin, gpio_interrupt_e interrupt_type, function_pointer_t callback);
+
+/**
+ * Allow the user to attach GPIO2 interrupt callback
+ * @param pin GPIO pin to be configured for GPIO interrupt
+ * @param interrupt_type Type of interrupt configuration
+ * @param callback An ISR function to be called on occurance of this interrupt
+ */
+void gpio2__attach_interrupt(uint32_t pin, gpio_interrupt_e interrupt_type, function_pointer_t callback);
+
+/**
+ * Dispatcher for the GPIO interrupt to recognise interrupting GPIO and call corresponding ISR
+ */
+void gpio__interrupt_dispatcher(void);
\ No newline at end of file
diff --git a/projects/lpc40xx_freertos/l3_drivers/sources/gpio_isr.c b/projects/lpc40xx_freertos/l3_drivers/sources/gpio_isr.c
new file mode 100644
index 0000000..234b5a6
--- /dev/null
+++ b/projects/lpc40xx_freertos/l3_drivers/sources/gpio_isr.c
@@ -0,0 +1,130 @@
+/**
+ * @file gpio_isr.c
+ * @author Tejas Pidkalwar
+ * @date 20th Sept 2020
+ * @brief This file maintains the abstracted APIs to configure GPIO interrupts
+ */
+
+#include "gpio_isr.h"
+#include "gpio.h"
+#include "stdio.h"
+/***************************GPIO 0********************************************/
+
+/**
+ * Array of callback ISR functions for GPIO 0 falling edge interrupts
+ */
+static function_pointer_t gpio0_falling_edge_callbacks[32];
+
+/**
+ * Array of callback ISR functions for GPIO 0 rising edge interrupts
+ */
+static function_pointer_t gpio0_rising_edge_callbacks[32];
+
+void gpio0__attach_interrupt(uint32_t pin, gpio_interrupt_e interrupt_type, function_pointer_t callback) {
+  printf("Attaching callback function for interrupt on GPIO 0 PIN %ld\n", pin);
+  // Attaching the callback function for given pin as per the given interrupt type
+  if (interrupt_type == GPIO_INTR__FALLING_EDGE) {
+    gpio0_falling_edge_callbacks[pin] = callback;
+    LPC_GPIOINT->IO0IntEnF |= (1 << pin);
+  } else {
+    gpio0_rising_edge_callbacks[pin] = callback;
+    LPC_GPIOINT->IO0IntEnR |= (1 << pin);
+  }
+}
+
+/***************************GPIO 2********************************************/
+
+/**
+ * Array of callback ISR functions for GPIO 2 falling edge interrupts
+ */
+static function_pointer_t gpio2_falling_edge_callbacks[32];
+
+/**
+ * Array of callback ISR functions for GPIO 2 rising edge interrupts
+ */
+static function_pointer_t gpio2_rising_edge_callbacks[32];
+
+void gpio2__attach_interrupt(uint32_t pin, gpio_interrupt_e interrupt_type, function_pointer_t callback) {
+  printf("Attaching callback function for interrupt on GPIO 2 PIN %ld\n", pin);
+  // Attaching the callback function for given pin as per the given interrupt type
+  if (interrupt_type == GPIO_INTR__FALLING_EDGE) {
+    gpio2_falling_edge_callbacks[pin] = callback;
+    LPC_GPIOINT->IO2IntEnF |= (1 << pin);
+  } else {
+    gpio2_rising_edge_callbacks[pin] = callback;
+    LPC_GPIOINT->IO2IntEnR |= (1 << pin);
+  }
+}
+
+/********************Common APIs**********************************************/
+
+/**
+ *  This function reads the status register to know which pin on GPIO0 has caused the interrupt
+ *  @param interrupt_type The pointer to the type of interrupt
+ *  @return pin return the pin that caused the interrupt
+ */
+static void update_interrupt_gpio_struct(gpio_interrupt_e *interrupt_type, gpio_s *gpio) {
+  uint32_t status;
+
+  // Read the GPIO interrupt registers to know interrupt causing GPIO specs
+  if (LPC_GPIOINT->IO0IntStatF) {
+    status = LPC_GPIOINT->IO0IntStatF;
+    *interrupt_type = GPIO_INTR__FALLING_EDGE;
+    gpio->port_number = 0;
+  } else if (LPC_GPIOINT->IO0IntStatR) {
+    status = LPC_GPIOINT->IO0IntStatR;
+    *interrupt_type = GPIO_INTR__RISING_EDGE;
+    gpio->port_number = 0;
+  } else if (LPC_GPIOINT->IO2IntStatF) {
+    status = LPC_GPIOINT->IO2IntStatF;
+    *interrupt_type = GPIO_INTR__FALLING_EDGE;
+    gpio->port_number = 1;
+  } else {
+    status = LPC_GPIOINT->IO2IntStatR;
+    *interrupt_type = GPIO_INTR__RISING_EDGE;
+    gpio->port_number = 1;
+  }
+
+  // get the pin number from the status register
+  int pin = 0;
+  while (status >>= 1)
+    pin++;
+  gpio->pin_number = pin;
+}
+
+/**
+ *  Clear the interrupt on a given pin of port 0.
+ *  @param pin pin number of which interrupt needs to be cleared
+ */
+static void gpio_clear_pin_interrupt(gpio_s gpio) {
+  if (gpio.port_number == 0)
+    LPC_GPIOINT->IO0IntClr |= (1 << gpio.pin_number);
+  else
+    LPC_GPIOINT->IO2IntClr |= (1 << gpio.pin_number);
+}
+
+void gpio__interrupt_dispatcher(void) {
+
+  gpio_interrupt_e interrupt_type;
+  gpio_s gpio;
+
+  // Check which pin generated the interrupt
+  update_interrupt_gpio_struct(&interrupt_type, &gpio);
+
+  function_pointer_t attached_user_handler;
+  if (gpio.port_number == 0) {
+    if (interrupt_type == GPIO_INTR__FALLING_EDGE)
+      attached_user_handler = gpio0_falling_edge_callbacks[gpio.pin_number];
+    else
+      attached_user_handler = gpio0_rising_edge_callbacks[gpio.pin_number];
+  } else {
+    if (interrupt_type == GPIO_INTR__FALLING_EDGE)
+      attached_user_handler = gpio0_falling_edge_callbacks[gpio.pin_number];
+    else
+      attached_user_handler = gpio0_rising_edge_callbacks[gpio.pin_number];
+  }
+  fprintf(stderr, "Dispatching to ISR fucntion corresponding to GPIO %d PIN %d\n", gpio.port_number, gpio.pin_number);
+  // Invoke the user registered callback, and then clear the interrupt
+  attached_user_handler();
+  gpio_clear_pin_interrupt(gpio);
+}
\ No newline at end of file
diff --git a/projects/lpc40xx_freertos/l5_application/main.c b/projects/lpc40xx_freertos/l5_application/main.c
index 3194d1d..63ad4cc 100644
--- a/projects/lpc40xx_freertos/l5_application/main.c
+++ b/projects/lpc40xx_freertos/l5_application/main.c
@@ -9,21 +9,132 @@
 #include "periodic_scheduler.h"
 #include "sj2_cli.h"
 
+#ifdef INTERRUPT_ASSIGNMENT
+
+#include "delay.h"
+#include "gpio_isr.h"
+#include "lpc_peripherals.h"
+#include "semphr.h"
+
+#endif
+
+#ifdef INTERRUPT_ASSIGNMENT
+
+void gpio_interrupt(void);
+static void sleep_on_sem_task(void *p);
+
+static SemaphoreHandle_t waitOnSemaphore;
+
+#else
+
 static void create_blinky_tasks(void);
 static void create_uart_task(void);
 static void blink_task(void *params);
 static void uart_task(void *params);
 
+#endif
+
 int main(void) {
+
+#ifdef INTERRUPT_ASSIGNMENT
+
+#ifdef PART0_IRQ_ASSGNMT
+  // Set GPIO 0 Pin 30 as a input
+  LPC_GPIO0->DIR &= ~(1 << 30);
+  LPC_GPIOINT->IO0IntEnR |= (1 << 30);
+
+  // lpc_peripheral__enable_interrupt(LPC_PERIPHERAL__GPIO, gpio_interrupt, "gpio0");
+
+  NVIC_EnableIRQ(GPIO_IRQn);
+
+  static gpio_s led2;
+
+  led2 = board_io__get_led2();
+  while (1) {
+    delay__ms(100);
+    gpio__toggle(led2);
+  }
+#endif
+
+#if (defined(PART1_IRQ_ASSGNMT) || defined(PART2_IRQ_ASSGNMT))
+  waitOnSemaphore = xSemaphoreCreateBinary();
+
+  // Initializing GPIO to switch 2 to configure for interrupt
+  static gpio_s switch2;
+  switch2 = board_io__get_sw2();
+
+  // Set GPIO 0 Pin 30 as a input
+  gpio__set_as_input(switch2);
+
+  NVIC_EnableIRQ(GPIO_IRQn);
+  xTaskCreate(sleep_on_sem_task, "waitOnSem", 2048 / sizeof(void *), NULL, PRIORITY_LOW, NULL);
+#endif
+
+#ifdef PART1_IRQ_ASSGNMT
+
+  LPC_GPIOINT->IO0IntEnR |= (1 << 30);
+  lpc_peripheral__enable_interrupt(LPC_PERIPHERAL__GPIO, gpio_interrupt, "gpio0");
+
+#endif
+
+#ifdef PART2_IRQ_ASSGNMT
+
+  gpio0__attach_interrupt(switch2.pin_number, GPIO_INTR__FALLING_EDGE, gpio_interrupt);
+
+  lpc_peripheral__enable_interrupt(LPC_PERIPHERAL__GPIO, gpio__interrupt_dispatcher, "gpio_isr");
+
+#endif
+
+#else
   create_blinky_tasks();
   create_uart_task();
-
+#endif
   puts("Starting RTOS");
   vTaskStartScheduler(); // This function never returns unless RTOS scheduler runs out of memory and fails
 
   return 0;
 }
 
+#ifdef INTERRUPT_ASSIGNMENT
+
+void gpio_interrupt(void) {
+  // Clear interrupt
+  LPC_GPIOINT->IO0IntClr |= (1 << 30);
+
+#ifdef PART0_IRQ_ASSGNMT
+  fprintf(stderr, "Switch is pressed, Enterring ISR to blink LED3\n");
+  static gpio_s led3;
+  led3 = board_io__get_led3();
+  int count = 4;
+  while (count--) {
+    delay__ms(100);
+    gpio__toggle(led3);
+  }
+#endif
+#if (defined(PART1_IRQ_ASSGNMT) || defined(PART2_IRQ_ASSGNMT))
+  fprintf(stderr, "Switch is pressed, Will enter Semaphore Task\n");
+  if (!xSemaphoreGiveFromISR(waitOnSemaphore, NULL))
+    fprintf(stderr, "Unable to Release Semaphore");
+#endif
+}
+
+static void sleep_on_sem_task(void *p) {
+  while (1) {
+    if (xSemaphoreTake(waitOnSemaphore, portMAX_DELAY)) {
+      fprintf(stderr, "ISR gave me semaphore to enter this task\n");
+      static gpio_s led3;
+      led3 = board_io__get_led3();
+      int count = 4;
+      while (count--) {
+        delay__ms(100);
+        gpio__toggle(led3);
+      }
+    }
+  }
+}
+
+#else
+
 static void create_blinky_tasks(void) {
   /**
    * Use '#if (1)' if you wish to observe how two tasks can blink LEDs
@@ -98,3 +209,5 @@ static void uart_task(void *params) {
     printf(" %lu ticks\n\n", (xTaskGetTickCount() - ticks));
   }
 }
+
+#endif
\ No newline at end of file
diff --git a/projects/lpc40xx_freertos/lpc40xx.h b/projects/lpc40xx_freertos/lpc40xx.h
index 2f138cb..9473013 100644
--- a/projects/lpc40xx_freertos/lpc40xx.h
+++ b/projects/lpc40xx_freertos/lpc40xx.h
@@ -27,6 +27,7 @@
 #ifndef __LPC407x_8x_H__
 #define __LPC407x_8x_H__
 
+#include "assignment_include.h"
 /*
  * ==========================================================================
  * ---------- Interrupt Number Definition -----------------------------------