20x2 LCD connection with TIVA C Launchpad (EK-TM4C123GXL)

I want to insert LCD datasheet here. Can you please tell from where I can insert that PDF doc. 

This is surely wrong (under Lcd Data)

GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_0|GPIO_PIN_1,0x02); //PD0=RS=0, PD1=E=1

This sets E high - yet drives RS low.  Terrible!   Both must be high - and should NOT toggle together!

GPIOPinWrite(GPIO_PORTD_BASE,GPIO_PIN_0|GPIO_PIN_1,0x03); //PD0=RS=1, PD1=E=1

Code above leaves both RS & E high - you want to drive E low at the completion of your display data write.

As Amit (and perhaps few others) have LONG noted - dreaded 0Ω resistors continue their long torment.   (God forbid they be properly "bagged" or tombstoned...)

Hello,

Thank you for your reply. sorry for the terrible mistake. I just noticed that after posting the query and changed pins from PD0, PD1 to PA6, PA7.

Left to their own devices (i.e. unguided) a 2-3 post issue extends to 10+... (wonderful - insures 100K points - but time/effort (value) is diluted and such inefficiency {even long & well identified} calls into question (other, perhaps more serious) misuse of time & resources...)

As I listed in the original (correcting) post - RS/RW & E must NOT toggle together.   This poster's code does that.   While wrong - this may work (until) the code changes from command to data write - and then the "together toggle" will disrupt the Lcd controller.

Hello,

Thank you for your suggestions. I have changed the code accordingly. Still the same issue continues, LCD continuously blinks .

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_memmap.h"
#include "inc/hw_types.h"
#include "driverlib/debug.h"
#include "driverlib/fpu.h"
#include "driverlib/gpio.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"
#include "utils/uartstdio.h"

//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
}
#endif

//LCD code
//PB0 to PB1 Data Lines
//PA6 = RS
//PA7 = E
//R/W = GND

void LCD_command(unsigned char data)
{
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); //PA6=PA7=0x00
GPIOPinWrite(GPIO_PORTB_BASE,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7,data); // DATA Pins
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); //PA6=PA7=0x00
SysCtlDelay(SysCtlClockGet()/3); // 1 sec delay
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x80); //PA6=0, PA7=1
SysCtlDelay(SysCtlClockGet()/3);
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); //PA6=PA7=0x00
}

void LCD_data(unsigned char data)
{
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); // PA6=PA7=0x00
GPIOPinWrite(GPIO_PORTB_BASE,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7,data); // DATA Pins
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x40); // PA6=1,PA7=0
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6,GPIO_PIN_6);// PA6=1, PA7=0
SysCtlDelay(SysCtlClockGet()/5);
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_7,GPIO_PIN_7);// PA6=1,PA7=1
SysCtlDelay(SysCtlClockGet()/3);
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_7,0x00); //PA7=0x00
SysCtlDelay(SysCtlClockGet()/3);
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); //PA6=PA7=0x00
}

void LCD_Init()
{
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x38); // function set
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x38); // function set
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x38); // function set
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x38); // function set
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x01); // clear display
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x06); // Entry mode set
SysCtlDelay(SysCtlClockGet()/3);
LCD_command(0x0C); // Display ON/OFF
SysCtlDelay(SysCtlClockGet()/3);
}

void LCD_String_Display(unsigned char*str)
{
SysCtlDelay(SysCtlClockGet()/3);
LCD_data(0x41); // display A
SysCtlDelay(SysCtlClockGet()/3);
LCD_data(0x43); // Display C
SysCtlDelay(SysCtlClockGet()/3);
LCD_data(0x44); // Display D
SysCtlDelay(SysCtlClockGet()/3);
while(*str);
{
LCD_data(*str);
str++;
}
}

int main(void)
{
SysCtlClockSet (SYSCTL_SYSDIV_16|SYSCTL_USE_PLL|SYSCTL_XTAL_16MHZ|SYSCTL_OSC_MAIN);
//ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
// SYSCTL_XTAL_16MHZ);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
GPIOPinTypeGPIOOutput(GPIO_PORTB_BASE,GPIO_PIN_0|GPIO_PIN_1|GPIO_PIN_2|GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7);
GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE,GPIO_PIN_6|GPIO_PIN_7);
LCD_Init();
LCD_String_Display("WELCOME");
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00);

}

// Please let me know if I am missing something. In LCD_data function I did the correction and now E goes high after RS signal.  I have a doubt the the *str loop does not get called. 

// Please help.

Our firm has just moved - we're over-loaded w/boxes - I'm not here "officially."

Your code has improved - but is ripe w/redundancies.   (i.e. you must spend more time in thought)

Lcd_Data still over-challenges:

GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x40); // PA6=1,PA7=0
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6,GPIO_PIN_6);// PA6=1, PA7=0

Do not those 2 lines do the same?   (you should be the proof-reader)

and

GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_7,0x00); //PA7=0x00
SysCtlDelay(SysCtlClockGet()/3);
GPIOPinWrite(GPIO_PORTA_BASE, GPIO_PIN_6|GPIO_PIN_7,0x00); //PA6=PA7=0x00

That 1st write clears "E" - that's fine.   Then the 2nd - clears both "E" & "RS" - when both were (already) clear.   Pointless...

Suggest that you employ KISS.   Forget your string command for now.  Employ a single character data write "0x41 for "A" - see if it works.

Depending upon your compiler settings - your delay loops may not be executing.  Failed delays & bad contrast settings are "usual suspects" for no display...