#include<stdint.h>
#include<stdbool.h>
#include"tm4c123gh6pm.h"

#define SW_bits 0x11
#define RED 0x02
#define BLUE 0x04
#define GREEN 0x08


/* Systick memory mapped registers */
#define STCTRL *((volatile long *) 0xE000E010)      // control and status
#define STRELOAD *((volatile long *) 0xE000E014)    // reload value
#define STCURRENT *((volatile long *) 0xE000E018)   // current value
#define ENABLE      (1 << 0)    // bit 0 of CSR to enable the timer
#define CLKINT      (1 << 2)    // bit 2 of CSR to specify CPU clock
#define SYS_INTEN      (1 << 1)    // enable systick interrupt

void UART_INIT()
{
    SYSCTL_RCGCGPIO_R |= 0x30;             // Enabling clock to Port E and Port F
    SYSCTL_RCGCUART_R |= (1<<7)|(1<<5);    // Enabling clock to UART 5th and 7th module
    GPIO_PORTE_LOCK_R = 0x4C4F434B;        // Unlocking commit registers
    GPIO_PORTE_CR_R |= 0xFF;               // commit register
    /* configuring PORT E pins as Alternate function selection register */
    GPIO_PORTE_AFSEL_R |= 0x33;            // configuring Port E 0 1 4 5 pins as alternate function
    GPIO_PORTE_PCTL_R |= (1<<20)|(1<<16)|(1<<4)|(1<<0);
    GPIO_PORTE_DIR_R = 0x33;               // setting PE5 and PE1 as output and PE4 and PE1 as input
    GPIO_PORTE_DEN_R |= 0x33;              // setting  digital pins

    // configuring UART 5 th module
    UART5_CTL_R &= ~(0x01);                // disabling uart 5 module
    UART5_IBRD_R =104;        // setting the baud rate as 9600
    UART5_FBRD_R = 11;        // setting baud rate as 9600
    UART5_LCRH_R =0x62;
    UART5_CC_R = 0;
    UART5_CTL_R |= ((1<<0)|(1<<8)|(1<<9));

    /* Configuring NVIC and interrupt for uart module 5*/
    /* UART5 has number 61 assigned for the interrupt vector table*/
    UART5_IM_R &= ((0<<4)|(0<<5)|(0<<8));       //Mask Tx, Rx and Parity interrupts
    UART5_ICR_R &= ((0<<4)|(0<<5)|(0<<8));      //Clear Tx, Rx and Parity interrupts
    UART5_IM_R |= (1<<4);                       //Enable Rx interrupt
    NVIC_EN1_R |= (1<<29);                      //Interrupts enabled for UART5
    NVIC_PRI15_R &= 0xFFFF5FFF;                 //Interrupt Priority 2 to UART5
}

void GPIO_INIT()
{
    // here we will configure the GPIO pins.
    /* switch 1 is connected to PF4 and switch 2 is connected to PF0 */
    GPIO_PORTF_LOCK_R = 0x4C4F434B;     //Unlock PortF register
    GPIO_PORTF_CR_R = 0x1F;             //Enable Commit function
    GPIO_PORTF_DIR_R = 0x0E;     // setting PF0  and PF4 as input pins
    GPIO_PORTF_DEN_R = 0x1F;     // digital enabling the pins.
    GPIO_PORTF_PUR_R = 0x11;     // enabling pullup resistors

    // configuring for interrupt
    GPIO_PORTF_IS_R &= ~SW_bits;        //Edge trigger detected
    GPIO_PORTF_IBE_R &= ~SW_bits;       //Trigger interrupt according to GPIOIEV
    GPIO_PORTF_IEV_R &= ~SW_bits;       //Trigger interrupt on falling edge
    GPIO_PORTF_IM_R &= ~SW_bits;        //Mask interrupt bits
    GPIO_PORTF_ICR_R |= SW_bits;        //clear any prior interrupts
    GPIO_PORTF_IM_R |= SW_bits;         //enable interrupts for bits corresponding to Mask_Bits
    // setting priorities using NVIC
    NVIC_EN0_R |=(1<<30);
    NVIC_PRI7_R &= 0xFF3FFFFF;


}

void GPIO_Intrpt_HANDLER()
{
    int x;
    x=GPIO_PORTF_MIS_R;
    GPIO_PORTF_IM_R &= ~SW_bits;//sw1 and sw2 masked

    /* pressing Switch 1 -> Send AA
     * pressing Switch 2 -> Send F0*/

    if(x & 0X10) //interrupt on switch 1
    {
        UART5_DR_R = 0xF0;

    }
    if(x & 0X01) // Interrupt on switch 2
    {
        UART5_DR_R = 0xAA;
    }


    //GPIO_PORTF_IM_R |= SW_bits;    // unmasking sw1 and sw2


}
void UART_Intrpt_HANDLER()
{   UART5_IM_R &= (0<<4);       //Mask UART Rx interrupt
    if(UART5_FR_R & (1<<6))
    {
        if(UART5_DR_R == 0xAA)
            GPIO_PORTF_DATA_R = GREEN;
        if(UART5_DR_R == 0XF0)
            GPIO_PORTF_DATA_R = BLUE;
    }

        if(UART5_RSR_R & 0x0F)
            GPIO_PORTF_DATA_R = RED;
    UART5_ECR_R &= 0xFFFFFFF0;        //Clear UART errors
    STRELOAD = 1000000*8;                  // for delay of 0.5 sec
    STCURRENT = 0;
    STCTRL |= (CLKINT | ENABLE | SYS_INTEN);    // set internal clock, enable the timer,enable interrupt
    GPIO_PORTF_ICR_R |= SW_bits;   // clearing the interrupt
}

void SYSTICK_HANDLER()
{
    GPIO_PORTF_DATA_R  = 0x00;            // turn off LED LED
    GPIO_PORTF_ICR_R = SW_bits;         // clear interrupt for port F
    GPIO_PORTF_IM_R |= SW_bits;        // unmask interrupts for sw1 and sw2
    UART5_IM_R |= (1<<4);
}

void main()
{
    UART_INIT();
    GPIO_INIT();
    while(1){}
}