why LCD does not display anything - c

Question

#include <stdio.h>
#include <stdlib.h>
#include <xc.h>
#include <string.h>
#include <stdint.h>
#include "config.h"
#include "Uart.h"
#define _XTAL_FREQ 20000000
#define RS RC0
#define EN RC1
#define D4 RC2
#define D5 RC3
#define D6 RC4
#define D7 RC5
/*
*
*/
void Lcd_Port(char a)
{
if(a & 1)
D4 = 1;
else
D4 = 0;
if(a & 2)
D5 = 1;
else
D5 = 0;
if(a & 4)
D6 = 1;
else
D6 = 0;
if(a & 8)
D7 = 1;
else
D7 = 0;
}
void Lcd_Cmd(char a)
{
RS = 0; // => RS = 0
Lcd_Port(a);
EN = 1; // => E = 1
__delay_ms(4);
EN = 0; // => E = 0
}
int Lcd_Clear()
{
Lcd_Cmd(0);
Lcd_Cmd(1);
}
void Lcd_Set_Cursor(char a, char b)
{
char temp,z,y;
if(a == 1)
{
temp = 0x80 + b - 1;
z = temp>>4;
y = temp & 0x0F;
Lcd_Cmd(z);
Lcd_Cmd(y);
}
else if(a == 2)
{
temp = 0xC0 + b - 1;
z = temp>>4;
y = temp & 0x0F;
Lcd_Cmd(z);
Lcd_Cmd(y);
}
}
void Lcd_Init()
{
Lcd_Port(0x00); // clear latches before enabling TRIS bits
__delay_ms(20);
Lcd_Cmd(0x03);
__delay_ms(5);
Lcd_Cmd(0x03);
__delay_ms(11);
Lcd_Cmd(0x03);
/////////////////////////////////////////////////////
Lcd_Cmd(0x02); //02H is used for Return home -> Clears the RAM and initializes the LCD
Lcd_Cmd(0x02);
Lcd_Cmd(0x08);//Select Row 1
Lcd_Cmd(0x00);//Clear Row 1 Display
Lcd_Cmd(0x0C);//Select Row 2
Lcd_Cmd(0x00);//Clear Row 2 Display
Lcd_Cmd(0x06);
}
void Lcd_Write_Char(char a)
{
char temp,y;
temp = a&0x0F;
y = a&0xF0;
RS = 1; // => RS = 1
Lcd_Port(y>>4); //Data transfer
EN = 1;
__delay_us(40);
EN = 0;
Lcd_Port(temp);
EN = 1;
__delay_us(40);
EN = 0;
}
void Lcd_Write_String(char *a)
{
int i;
for(i=0;a[i]!='\0';i++)
Lcd_Write_Char(a[i]);
}
void Lcd_Shift_Right()
{
Lcd_Cmd(0x01);
Lcd_Cmd(0x0C);
}
void Lcd_Shift_Left()
{
Lcd_Cmd(0x01);
Lcd_Cmd(0x08);
}
int main(int argc, char** argv) {
OSCCONbits.IRCF = 0b1111; //set operating frequency to 31kHz (0b1111) for 16MHz
UART_init();
Lcd_Init();
// ->Setare Pini
//Pini motor DC
ANSELAbits.ANSA0 = 0; //set to digital pin
ANSELAbits.ANSA1 = 0; //set to digital pin
TRISAbits.TRISA0 = 0; //set as output
TRISAbits.TRISA1 = 0; //set as output
PORTAbits.RA0 = 0;
PORTAbits.RA1 = 0;
//Butoane
ANSELAbits.ANSA2 = 0; //set to digital pin
ANSELAbits.ANSA4 = 0; //set to digital pin
ANSELBbits.ANSB4 = 0; //set to digital pin
TRISAbits.TRISA2 = 1; //set as input
TRISAbits.TRISA4 = 1; //set as input
TRISBbits.TRISB4 = 1; //set as input
//LEDuri
//RC6 - RIGHT
//RC6 LEFT
TRISCbits.TRISC6 = 0;
TRISCbits.TRISC7 = 0;
//Set as digital
ANSELCbits.ANSC6 = 0;
ANSELCbits.ANSC7 = 0;
//Folosire LCD
TRISCbits.TRISC0 = 0; //set as output
TRISCbits.TRISC1 = 0; //set as output
TRISCbits.TRISC2 = 0; //set as output
TRISCbits.TRISC3 = 0; //set as output
TRISCbits.TRISC4 = 0; //set as output
TRISCbits.TRISC5 = 0; //set as output
//pull up
//pull upurile
OPTION_REGbits.nWPUEN = 0;
WPUAbits.WPUA2 = 1;
WPUAbits.WPUA4 = 1;
WPUAbits.WPUA0 = 1;
WPUAbits.WPUA1 = 0;
WPUAbits.WPUA3 = 0;
WPUAbits.WPUA5 = 0;
WPUBbits.WPUB4 = 1;
char introducere;
UART_write_string("1. Move to right ");
UART_write('\r');
UART_write_string("2. Move to left");
UART_write('\r');
UART_write_string("4. Stop UART");
UART_write('\r');
PORTCbits.RC6 = 0;
PORTCbits.RC7 = 0;
while(1){
introducere = UART_read();
if (introducere == '1'){
PORTAbits.RA0 = 1;
PORTAbits.RA1 = 0;
PORTCbits.RC6 = 1;
PORTCbits.RC7 = 0;
Lcd_Clear();
Lcd_Set_Cursor(1,1); //Go to the first line
Lcd_Write_String("helo"); //Display String
}
if (introducere == '2' ){
PORTAbits.RA0 = 0;
PORTAbits.RA1 = 1;
PORTCbits.RC6 = 0;
PORTCbits.RC7 = 1;
}
if(PORTAbits.RA2 == 0){ //Right
PORTAbits.RA0 = 1;
PORTAbits.RA1 = 0;
PORTCbits.RC6 = 1;
PORTCbits.RC7 = 0;
}
if(PORTAbits.RA4 == 0){ //left
PORTAbits.RA0 = 0;
PORTAbits.RA1 = 1;
}
if(introducere =='4'){
CREN = 0; //disable receiver
UART_write('\r');
UART_write_string("disable UART!");
UART_write('\r');
}
if(PORTBbits.RB4 == 0){
CREN = 1; //enable receiver
UART_write('\r');
UART_write_string("enable UART!");
UART_write('\r');
}
}
return (EXIT_SUCCESS);
}
The purpose of the project is to create a Dc motor which when we press 1 to rotate to the right and display on the LCD "rotated right", and if we press 2 to rotate to the left and display on the LCD "rotate left".
Used: pic16f1828
LCD: LM016L
I connected: RS (LCD) -> RC0 (pic), EN -> RC1, D4 -> RC2, D5 -> RC3, D6 -> RC4, D7 -> RC5
The program works well, the only problem I have is the fact that when I press "1" I want HELO to appear on LCD (it doesn't matter the arrangement). Till now it does not appear on LCD, is not just about HELLo, nothing is displayed, I can only see that it starts, I don't understand where the problem is.

Answer 1

Your implementation for writing to the HD44780 using a 4-bit parallel interface is wrong.
This is a complete, builds with MPLABX v5.50 and XC8 v2.32, demo that does display "Hello" on line 1 of the LCD module:
/*
* File: main.c
* Author: dan1138
* Target: PIC16F1828
* Compiler: XC8 v2.32
* IDE: MPLABX v5.50
*
* Created on January 23, 2022, 11:27 AM
*
* PIC16F1828
* +-----------:_:-----------+
* VDD -> : 1 VDD VSS 20 : <- VSS
* RA5 <> : 2 OSC2 PGD 19 : <> RA0 ICD_PGD
* RA4 <> : 3 OSC1 PGC 18 : <> RA1 ICD_PGC/D5
* ICD_VPP RA3 -> : 4 VPP/MCLRn 17 : <> RA2
* LCD_D7 RC5 <> : 5 16 : <> RC0 LCD_RS
* LCD_D6 RC4 <> : 6 15 : <> RC1 LCD_EN
* LCD_D5 RC3 <> : 7 14 : <> RC2 LCD_D4
* RC6 <> : 8 13 : <> RB4
* RC7 <> : 9 12 : <> RB5
* RB7 <> : 10 11 : <> RB6
* +-------------------------+
* DIP-20
*
* Description:
*
* See: https://stackoverflow.com/questions/70800375/why-lcd-does-not-display-anything
*/
// CONFIG1
#pragma config FOSC = INTOSC // Oscillator Selection (INTOSC oscillator: I/O function on CLKIN pin)
#pragma config WDTE = OFF // Watchdog Timer Enable (WDT disabled)
#pragma config PWRTE = OFF // Power-up Timer Enable (PWRT disabled)
#pragma config MCLRE = ON // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config CP = OFF // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config CPD = OFF // Data Memory Code Protection (Data memory code protection is disabled)
#pragma config BOREN = OFF // Brown-out Reset Enable (Brown-out Reset disabled)
#pragma config CLKOUTEN = OFF // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
#pragma config IESO = ON // Internal/External Switchover (Internal/External Switchover mode is enabled)
#pragma config FCMEN = ON // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is enabled)
// CONFIG2
#pragma config WRT = OFF // Flash Memory Self-Write Protection (Write protection off)
#pragma config PLLEN = OFF // PLL Enable (4x PLL disabled)
#pragma config STVREN = ON // Stack Overflow/Underflow Reset Enable (Stack Overflow or Underflow will cause a Reset)
#pragma config BORV = LO // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config LVP = ON // Low-Voltage Programming Enable (Low-voltage programming enabled)
/*
* Tell compiler what we intend to set the system oscillator frequency as.
*/
#define _XTAL_FREQ (16000000UL)
#include <xc.h>
#include <stdio.h>
/* Define the LCD interface and character size */
#define LCD_FORMAT (FOUR_BIT & LINES_5X7)
/* Define the LCD port pins */
#define LCD_DATA_BITS_MASK 0x3C
#define LCD_PORT_OUT LATC
#define LCD_PORT_DIR TRISC
#define LCD_RS_PIN LATCbits.LATC0
#define LCD_EN_PIN LATCbits.LATC1
#define LCD_D4_PIN LATCbits.LATC2
#define LCD_D5_PIN LATCbits.LATC3
#define LCD_D6_PIN LATCbits.LATC4
#define LCD_D7_PIN LATCbits.LATC5
#define LCD_RS_PIN_DIR TRISCbits.TRISC0
#define LCD_EN_PIN_DIR TRISCbits.TRISC1
#define LCD_D4_DIR TRISCbits.TRISC2
#define LCD_D5_DIR TRISCbits.TRISC3
#define LCD_D6_DIR TRISCbits.TRISC4
#define LCD_D7_DIR TRISCbits.TRISC5
/* Clear display command */
#define CLEAR_DISPLAY 0b00000001
/* Return home command */
#define RETURN_HOME 0b00000010
/* Display ON/OFF Control defines */
#define DON 0b00001111 /* Display on */
#define DOFF 0b00001011 /* Display off */
#define CURSOR_ON 0b00001111 /* Cursor on */
#define CURSOR_OFF 0b00001101 /* Cursor off */
#define BLINK_ON 0b00001111 /* Cursor Blink */
#define BLINK_OFF 0b00001110 /* Cursor No Blink */
/* Cursor or Display Shift defines */
#define SHIFT_CUR_LEFT 0b00010011 /* Cursor shifts to the left */
#define SHIFT_CUR_RIGHT 0b00010111 /* Cursor shifts to the right */
#define SHIFT_DISP_LEFT 0b00011011 /* Display shifts to the left */
#define SHIFT_DISP_RIGHT 0b00011111 /* Display shifts to the right */
/* Function Set defines */
#define FOUR_BIT 0b00101111 /* 4-bit Interface */
#define EIGHT_BIT 0b00111111 /* 8-bit Interface */
#define LINE_5X7 0b00110011 /* 5x7 characters, single line */
#define LINE_5X10 0b00110111 /* 5x10 characters */
#define LINES_5X7 0b00111011 /* 5x7 characters, multiple line */
/* Start address of each line */
#define LINE_ONE 0x00
#define LINE_TWO 0x40
static void LCD_E_Pulse(void)
{
LCD_EN_PIN = 1;
__delay_us(4);
LCD_EN_PIN = 0;
__delay_us(4);
}
static void LCD_DelayPOR(void)
{
__delay_ms(15);
}
static void LCD_Delay(void)
{
__delay_ms(5);
}
static void LCD_PutByte(unsigned char LCD_Data)
{
LCD_PORT_DIR &= ~LCD_DATA_BITS_MASK; /* make LCD data bits outputs */
/* send first(high) nibble */
LCD_PORT_OUT &= ~LCD_DATA_BITS_MASK;
if(LCD_Data & 0x10) LCD_D4_PIN = 1;
if(LCD_Data & 0x20) LCD_D5_PIN = 1;
if(LCD_Data & 0x40) LCD_D6_PIN = 1;
if(LCD_Data & 0x80) LCD_D7_PIN = 1;
LCD_E_Pulse();
/* send second(low) nibble */
LCD_PORT_OUT &= ~LCD_DATA_BITS_MASK;
if(LCD_Data & 0x01) LCD_D4_PIN = 1;
if(LCD_Data & 0x02) LCD_D5_PIN = 1;
if(LCD_Data & 0x04) LCD_D6_PIN = 1;
if(LCD_Data & 0x08) LCD_D7_PIN = 1;
LCD_E_Pulse();
LCD_PORT_DIR |= LCD_DATA_BITS_MASK; /* make LCD data bits inputs */
}
void LCD_SetPosition(unsigned char data)
{
LCD_RS_PIN = 0;
LCD_PutByte((unsigned char)(data | 0x80));
__delay_us(40);
}
void LCD_WriteCmd(unsigned char data)
{
LCD_RS_PIN = 0;
LCD_PutByte(data);
__delay_ms(4);
}
void LCD_WriteData(unsigned char data)
{
LCD_RS_PIN = 1;
LCD_PutByte(data);
LCD_RS_PIN = 0;
__delay_us(40);
}
void LCD_Init(void)
{
unsigned char LCD_Data;
LCD_PORT_DIR &= ~LCD_DATA_BITS_MASK; /* make LCD data bits outputs */
LCD_EN_PIN_DIR = 0; /* make LCD Enable strobe an output */
LCD_RS_PIN_DIR = 0; /* make LCD Register select an output */
LCD_EN_PIN = 0; /* set LCD Enable strobe to not active */
LCD_RS_PIN = 0; /* set LCD Register select to command group */
LCD_PORT_OUT &= ~LCD_DATA_BITS_MASK; /* set LCD data bits to zero */
LCD_DelayPOR(); /* wait for LCD power on to complete */
/* Force LCD to 8-bit mode */
LCD_PORT_OUT &= ~LCD_DATA_BITS_MASK; /* set LCD data bits to zero */
LCD_D4_PIN = 1;
LCD_D5_PIN = 1;
LCD_E_Pulse();
LCD_Delay();
LCD_E_Pulse();
LCD_Delay();
LCD_E_Pulse();
LCD_Delay();
/* Set LCD to 4-bit mode */
LCD_PORT_OUT &= ~LCD_DATA_BITS_MASK; /* set LCD data bits to zero */
LCD_D5_PIN = 1;
LCD_E_Pulse();
LCD_Delay();
/* Initialize LCD mode */
LCD_WriteCmd(LCD_FORMAT);
/* Turn on display, Setup cursor and blinking */
LCD_WriteCmd(DOFF & CURSOR_OFF & BLINK_OFF);
LCD_WriteCmd(DON & CURSOR_OFF & BLINK_OFF);
LCD_WriteCmd(CLEAR_DISPLAY);
LCD_WriteCmd(SHIFT_CUR_LEFT);
/* Set first position on line one, left most character */
LCD_SetPosition(LINE_ONE);
}
/*
* Hook for printf
*/
void putch(char txData)
{
LCD_WriteData(txData);
}
/*
* Main application
*/
void main(void)
{
OSCCON = 0x7A; //set operating frequency to 16MHz
ANSELA = 0;
ANSELB = 0;
ANSELC = 0;
//pull up
OPTION_REGbits.nWPUEN = 0;
WPUAbits.WPUA2 = 1;
WPUAbits.WPUA4 = 1;
WPUAbits.WPUA0 = 1;
WPUAbits.WPUA1 = 0;
WPUAbits.WPUA3 = 0;
WPUAbits.WPUA5 = 0;
LCD_Init();
__delay_ms(100);
LCD_SetPosition(LINE_ONE);
printf("Hello");
/*
* Application loop
*/
for(;;)
{
}
}