interfacing of tiva c series microcontroller with keypad

#include <stdint.h>

#include <stdbool.h>

#include "inc/hw_types.h"

#include "inc/hw_memmap.h"

#include "driverlib/sysctl.h"
#include "driverlib/pin_map.h"
#include "driverlib/gpio.h"
#include "driverlib/uart.h"



uint8_t k;

//function to detect which key is pressed
uint8_t key_detect()

{

GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_2 | GPIO_PIN_3, 0x08);

if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2)==0x00) return(0);

else if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)==0x00) return(1);



GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_2 | GPIO_PIN_3, 0x04);

if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2)==0x00) return(2);

else if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)==0x00) return(3);

if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)!=0x00 && GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2)!=0x00)
	return(6);
}



void key_function(uint8_t key)

{

switch(key)

{

case 0: SysCtlDelay(13333334);
UARTCharPut(UART0_BASE, '0');break;

case 1: SysCtlDelay(13333334);
UARTCharPut(UART0_BASE, '1');break;

case 2: SysCtlDelay(13333334);
UARTCharPut(UART0_BASE, '2');break;

case 3: SysCtlDelay(13333334);
UARTCharPut(UART0_BASE, '3');break;

//prints 6 when no key is pressed
case 6: SysCtlDelay(13333334);
UARTCharPut(UART0_BASE, '6');break;



}

}

int main(void)

{

// Tiva C LaunchPad System Initialisation //

SysCtlClockSet(SYSCTL_SYSDIV_5 | SYSCTL_USE_PLL| SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);


//ENABLING PORTS

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOD);

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOE);

SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);


//DEFINING THE PINS


//pins of PORT F are connected to the LEDs
GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3);


//pins of PORT D are connected to rows 1,2 of the keypad
GPIOPinTypeGPIOOutput(GPIO_PORTD_BASE, GPIO_PIN_2 | GPIO_PIN_3);

//pins of PORT E are connected to column 1,2 of the keypad
GPIOPinTypeGPIOOutput(GPIO_PORTE_BASE, GPIO_PIN_2 | GPIO_PIN_3);


// End of Tiva C LaunchPad System Initialisation //



// Wait 1 Millisecond after LCD Power Up //

SysCtlDelay(13333);


//making the rows 1,2 zero connected to PORTD
GPIOPinWrite(GPIO_PORTD_BASE, GPIO_PIN_2 | GPIO_PIN_3, 0x00);

SysCtlDelay(13333334);

//configuring UART
SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
GPIOPinConfigure(GPIO_PA0_U0RX);
GPIOPinConfigure(GPIO_PA1_U0TX);

//defining the UART pins at PORTA 0,1
GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 |GPIO_PIN_1);

UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(),115200,(UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |UART_CONFIG_PAR_NONE));



GPIOPinWrite(GPIO_PORTE_BASE, GPIO_PIN_2 | GPIO_PIN_3, 0x0c);


//To check whether the write operation has be done properly or not,if done properly blue LED glows

if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)==0x08)
{
      //blue LED glows
	 GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1| GPIO_PIN_2| GPIO_PIN_3, 0x04);
}
if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)==0x00)
{
           
     //green LED glows
	 GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1| GPIO_PIN_2| GPIO_PIN_3, 0x08);
}

SysCtlDelay(133333349);

// Loop for detecting key press and key function //
while(1)

{

//Reading the value of column 1 of keypad connected at PORTE
if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2)==0x00)

{
   //glowing of LED
   GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1| GPIO_PIN_2| GPIO_PIN_3, 0x08);

   SysCtlDelay(13333334);

   k=key_detect();

   key_function(k);

}

else if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)==0x00)

{

  GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_1| GPIO_PIN_2| GPIO_PIN_3, 0x02);

  SysCtlDelay(13333334);

 
  k=key_detect();

key_function(k);

}

//if no key is pressed
else if(GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_3)!=0x00 && GPIOPinRead(GPIO_PORTE_BASE, GPIO_PIN_2)!=0x00)
{
	SysCtlDelay(13333334);
	 k=key_detect();
	 key_function(k);
}

}

// End of loop for detecting key press and key function //

}