[SOLVED] LCD Connection with PIC32MX250F128D

rajib.das · Jun 18, 2015

Hi guys

I am trying to connect a 16x2 3.3V LCD with PIC32MX250F128D. Spent lot of time with no positive result. Please help me.

The following code will explain my connections.

Code:

// LCD module connections
sbit LCD_RS at LATA10_bit;
sbit LCD_EN at LATA7_bit;
//
sbit LCD_D4 at LATC6_bit;
sbit LCD_D5 at LATC7_bit;
sbit LCD_D6 at LATC8_bit;
sbit LCD_D7 at LATC9_bit;
//
sbit LCD_BackPW at LATA8_bit;     


 
//
sbit LCD_RS_Direction at TRISA10_bit;
sbit LCD_EN_Direction at TRISA7_bit;
//
sbit LCD_D4_Direction at TRISC6_bit;
sbit LCD_D5_Direction at TRISC7_bit;
sbit LCD_D6_Direction at TRISC8_bit;
sbit LCD_D7_Direction at TRISC9_bit;

sbit LCD_BackPW_Direction at TRISA8_bit;
// End LCD module connections



char txt1[] = "mikroElektronika";
char txt2[] = "Its a Test";


  LCD_BackPW = 0; //Clear PORTD by setting to 0
  LCD_BackPW_Direction = 0;   // designate PORTB2 pins as output
  
  Lcd_Init();                        // Initialize LCD
  LCD_BackPW = 1;
  
void main(){

  Lcd_Cmd(_LCD_CLEAR);               // Clear display
  Lcd_Cmd(_LCD_CURSOR_OFF);          // Cursor off
  Lcd_Out(1,1,txt1);                 // Write text in first row
  Lcd_Out(2,1,txt2);                 // Write text in second row
  Delay_ms(2000);

  while(1) { 

  
  }

}

FYI I am using Pin21 as PGED1 and Pin22 as PGEC1 for Programming and its working. Oscillator Frequency [MHz] is 10.000000.

Please advise if you can. Thanks in advance.

horace1 · Jun 18, 2015

here is the code for driving the LCD of a Microchip Explorer 16 with PIC32MX360F512L using MPLABX with the XC32 compiler

Code:

// lcd.c -  Explorer 16 with PIC32MX360F512L 
// functions for the PC1602-J lcd display 8-bit mode
//
// see http://www.repairfaq.org/filipg/LINK/F_LCD_progr.html

#include "hardware.h"
#include "timer.h"
#include "lcd.h"

// LCD display ports etc
#define LCDdata LATE					// data port
#define LCDdataEnable	TRISE
#define RS LATBbits.LATB15				// RS bit in LCDstatus
#define RW LATDbits.LATD5				// read/write bit in LCDstatus
#define E  LATDbits.LATD4   			// enable bit in LCDstatus
#define Eenable TRISDbits.TRISD4
#define ERSenable TRISDbits.TRISD5
#define RWenable TRISBbits.TRISB15

void lcd_delay() { mSecDelay(1); }  // if LCD does not work make this longer

// Write a byte to the LCD
// may have to adjust delays to suit the processor and clock
void lcdByte(int n)
{
	lcd_delay();
    LCDdata=n;
	lcd_delay();
    E=1;					// take clock E high 
	lcd_delay();
    E=0;
	lcd_delay();
 }

// Write a Control Command to the LCD
// This is written as two nibbles
void lcdCmd(int c)
{
 	RS=0;			        // Take RS pin low for command
	lcdByte(c);			        // Makeup Lower Nibble
}

// write a data byte to LCD
int lcdPutchar(int d)
{
//    printf("%c", d);
	RS=1; 				// Take RS pin high for data
	lcdByte(d);		            // Makeup Lower Nibble
    return 1;
}

// Initialise the LCD in 4bit Mode
void lcdInit()
{
	E=0;				// take E low
 	RS=0;				// Take RS pin low for command
 	RW=0;				// Take RS pin low for command
    // set RS, RW and E bits as output
	Eenable =0;
	ERSenable =0;
	RWenable =0;
    LCDdataEnable &= 0x0;          // set bits 0-3 output for data
	lcdByte(0x3);		// This put the LCD into Soft Reset 
	lcdByte(0x3);
	lcdByte(0x3);
	lcdByte(0x2);
	lcd_delay();
//	lcdCmd(0x28);			// 2 line, 4 bit mode 
	lcdCmd(0x38);			// 2 line, 8 bit mode 
	lcd_delay();
    lcdCmd(0x6);			// increment cursor after each write
	lcd_delay();
    lcdCmd(0x1);			// clear display
	lcd_delay();
    lcdCmd(0x2);			// home
	lcd_delay();
    lcdCmd(0xF);			// turn disply on
	lcd_delay();
}

// move to line (1 or 2) at position >= 1
void lcdCursor(unsigned char line,unsigned char position)
{
   switch (line)
	{
	  case 1:lcdCmd (0x80 + position -1 );lcdCmd (0x80 + position -1 ); break;
	  case 2:lcdCmd (0xc0 + position -1 ); lcdCmd (0xc0 + position -1 ); break;
	  default : break;
  	}
  lcd_delay();
}

void lcdString(unsigned char line, unsigned char position, unsigned char *string)
{

	lcdCursor(line,position);
	while (*string)
	  lcdPutchar(*string++);

}

void lcdStringAtCursor(unsigned char *string)
{

	while (*string)
	  lcdPutchar(*string++);
}

void lcdClear(void)
{
	lcdCmd(0x01);
}

void lcdHome(void)
{
	lcdCmd(0x02);
}


// clear line 1 or line 2
void lcdClearLine(unsigned char line)
{
	unsigned char i;
	lcdCursor(line,1);
	for (i=0; i<16; i++) lcdPutchar(' ');
	lcdCursor(line,1);
}

rajib.das · Jun 29, 2015

Thanks Horace1.
My problem is I have to Use MikroC pro PIC32 for this project. And I am missing lcd.h, hardware.h files.
All the example programs Mikroc pro for PIC32 gave us are all for PIC32MX460F512L. and I don't think their library files are quite suiting PIC32MX250F128D. That's not a expected result from a 250$ product.

Is there anyone can help me on this to make this work. I am sure I am missing something to configure these pins properly.
MY pin configuration would be

sbit LCD_RS at LATA10_bit;
sbit LCD_EN at LATA7_bit;
//
sbit LCD_D4 at LATC6_bit;
sbit LCD_D5 at LATC7_bit;
sbit LCD_D6 at LATC8_bit;
sbit LCD_D7 at LATC9_bit;

FYI : I am using PGEC1/PGED1 for Programming.

horace1 · Jun 29, 2015

the lcd.h and hardware.h header files only contain function prototypes and a few consctant for the timer and uart function

assuming your LCD hardware interface is similar to the Explorer 16 the code in post #2 should give you sufficent information to convert it to Microc
e.g. these statements define the pins used (change the declarations to suit your hardware and microC)

Code:

// LCD display ports etc
#define LCDdata LATE					// data port
#define LCDdataEnable	TRISE
#define RS LATBbits.LATB15				// RS bit in LCDstatus
#define RW LATDbits.LATD5				// read/write bit in LCDstatus
#define E  LATDbits.LATD4   			// enable bit in LCDstatus
#define Eenable TRISDbits.TRISD4
#define ERSenable TRISDbits.TRISD5
#define RWenable TRISBbits.TRISB15

and these statements set them up followed by code to initialise the LCD (this sets up 8 bits mode but there is a commented out line to set up 4 bit mode)

Code:

// Initialise the LCD in 4bit Mode
void lcdInit()
{
	E=0;				// take E low
 	RS=0;				// Take RS pin low for command
 	RW=0;				// Take RS pin low for command
    // set RS, RW and E bits as output
	Eenable =0;
	ERSenable =0;
	RWenable =0;
    LCDdataEnable &= 0x0;          // set bits 0-3 output for data
	lcdByte(0x3);		// This put the LCD into Soft Reset 
	lcdByte(0x3);
	lcdByte(0x3);
	lcdByte(0x2);
	lcd_delay();
//	lcdCmd(0x28);			// 2 line, 4 bit mode 
	lcdCmd(0x38);			// 2 line, 8 bit mode 
	lcd_delay();
    lcdCmd(0x6);			// increment cursor after each write
	lcd_delay();
    lcdCmd(0x1);			// clear display
	lcd_delay();
    lcdCmd(0x2);			// home
	lcd_delay();
    lcdCmd(0xF);			// turn disply on
	lcd_delay();
}

you should then be able to write to the LCD with statements such as

Code:

  lcdCursor(1,1);
   lcdStringAtCursor("Explorer 16");

if you are using 4 bit mode you will have to modify void lcdByte(int n) to write two 4 bit values, e.g.

Code:

// Write a nibble to the LCD
// may have to adjust delays to suit the processor and clock
void lcdNibble(int n)
{
    int lcd=LCDdata;
	lcd_delay();
  	LCDdata = (lcd&0xfff0) | ((n & 0x0f));			// send out lower Nibble
	lcd_delay();
    LCDstatus.E=1;					// take clock E high 
	lcd_delay();
    LCDstatus.E=0;
	lcd_delay();
 }

// Write a byte to the LCD
// This is written as two nibbles
void lcdByteint c)
{
 	LCDstatus.RS=0;			        // Take RS pin low for command
	lcdNibble(c >>4);		        // Makeup Upper Nibble
	lcdNibble(c);			        // Makeup Lower Nibble
}

rajib.das · Jun 29, 2015

Thanks Horace1. Its really working!!!!! Both of your and Mikroc's LCD library working 100%.
By mistake I did setup the internal clock too high. All I had to do to set up the external clock to 8 MHz.

Thanks Everyone.

[SOLVED] LCD Connection with PIC32MX250F128D

rajib.das

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horace1

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rajib.das

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