trouble in interfacing LCD to PIC16f877a

Hello,
Please check the following HiTech C code for 16x2 LCD interfacing.
The 1st line of LCD shows blocks.The code is taken from the Samples and only the connection bits are changed.
But,its not working.
However,if I write similar code in microC,it works.So the connections are right.
Please help.
Thank You.


Also note,the HTC code is working in Proteus ISIS.

yes, the code is working properly on ISIS,and yes the connections are fine too .
two things that are confusing me
1. the ISIS dig. for Pic16f877a and the one in data sheet are showing different positions of PORTD- 0 & 1 pins
2. are the < configuration bits > and the <XTal frequency causing this trouble.

Post the circuit? Is your Config settings right? Have you included HS_OSC in Config? Delay is not sufficient. Change Fosc to 4 MHz and see if it works else increase delays. If 4 MHz is used change OSC to XT_OSC in Config.

these lines are written in the code ..
[[#define _xtal_freq 16000000;
__CONFIG (0x2F0A);]]
delay value given is [ 250 ] .. (as given in the code in the 1st pdf uploaded)
* do you want to make Xtal frequency =4mhz ?*




also please confirm that denoting first pin of PORT B by [[ RB1 ]] is right or not
i.e. #define en RB1 ??

Vss of LCD should be connected to ground and Vee pin should be connected to pot wiper and pot to +5V. Pot should be 5K or 10K.

the hardware lcd i am using is on a development board so the pins Vss Vcc and Vee are already connected to the required terminals internally.There's nothing i can do in it except controlling the contrast through the potentiometer .
Can you please elaborate on the freq and config points , i suppose a mistake there

Consider the datasheet for good pins connections;VSS,VDD and VEE.

Hope its helpfull.

Nothing still ..
can you tell
1. how to define first port of PORT B in MPLAB using hitech c compiler for pic16f877a
2. what should be the configuration bits set
3. the xtal frequency defined

Post the codes here.

i have already posted the code in the first post itself as an attachment ..
here it is [[ it displays M D E to the lcd using two functions 1. lcddata 2. lcdcmd and a simple delay function

#include<htc.h>
#define _xtal_freq 16000000;
__CONFIG (0x2F0A);

#define ldata PORTD
#define rs RB0
#define rw RB1
#define en RB2

void MSDelay(unsigned int itime);
void lcdcmd(unsigned char value);
void lcddata(unsigned char value);

void main()
{
TRISD = 0x00;
TRISB = 0x00;
en=0;

MSDelay(250);
lcdcmd(0x38);
MSDelay(250);
lcdcmd(0x0E);
MSDelay(150);
lcdcmd(0x01);
MSDelay(250);
lcdcmd(0x06);
MSDelay(250);
lcdcmd(0x86);
MSDelay(250);
lcddata('M');
MSDelay(250);
lcddata('D');
MSDelay(250);
lcddata('E');
}

void lcdcmd(unsigned char value)
{
ldata = value;

rs=0;
rw=0;
en=1;
MSDelay(100);
en=0;
MSDelay(100);
}

void lcddata(unsigned char value)
{
ldata = value;
rs=1;
rw=0;
en=1;
MSDelay(100);
en=0;
MSDelay(100);
}

void MSDelay(unsigned int itime)
{
unsigned int i,j;
for(i=0;i<itime;i++)
for(j=0;j<72;j++)
{}
}

Try this with 4 MHz clock. Turn off code optimization. maybe optimization is removing the delay code.

HOW exactly do i turn off code optimisation ?

jayanth.devarayanadurga said:

Try this with 4 MHz clock. Turn off code optimization. maybe optimization is removing the delay code.

---

Code C - [expand]
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#include<htc.h>
 
#define _xtal_freq 4000000;
 
    __CONFIG(FOSC_XT & WDTE_OFF & PWRTE_ON & CP_OFF & BOREN_ON 
            & LVP_OFF & DEBUG_OFF);
 
#define ldata PORTD
#define rs RB0
#define rw RB1
#define en RB2
 
void MSDelay(unsigned int itime);
void lcdcmd(unsigned char value);
void lcddata(unsigned char value);
 
void main()
{
    TRISD = 0x00;
    TRISB = 0x00;
    
 
    MSDelay(250);
    lcdcmd(0x38);
    MSDelay(250);
    lcdcmd(0x0E);
    MSDelay(15);
    lcdcmd(0x01);
    MSDelay(25);
    lcdcmd(0x06);
    MSDelay(25);
    lcdcmd(0x86);
    MSDelay(25);
    lcddata('M');
    MSDelay(25);
    lcddata('D');
    MSDelay(250);
    lcddata('E');
 
    while(1);
 
}
 
void lcdcmd(unsigned char value)
{
    ldata = value;
 
    rs=0;
    rw=0;
    en=1;
    MSDelay(1);
    en=0;
 
}
 
void lcddata(unsigned char value)
{
    ldata = value;
    rs=1;
    rw=0;
    en=1;
    MSDelay(1);
    en=0;
}
 
void MSDelay(unsigned int itime)
{ 
    unsigned int i,j;
 
    for(i=0;i<itime;i++)
        for(j=0;j<72;j++)
    
}

---

Click to expand...

See attached image. Set level to 0. 0 = no optimization.

the minimum allowed value is [ 1 ] for optimization.
still not working. as you are having the code can you check if it is working or not.

It is working in Proteus. I don't have PIC16F877A with me now. Use 4 MHz Crystal or increase the delay and see. Try to use Hi-Tech C delay library routine for the delays.