lcd interface

COMPLETE INTERFACING LCD WITH MICRO-CONTROLLER USING C-PROGRAMMING

STEPS 

1. What is LCD? Which LCD are we going to use ? What is the LCD address bit ? 

   -  Here I'm going to use is the 16*2 LCD .total of 16 pins. It has 8 bit data address(can also be used for 4 bit addressing ) i.e it can carry out the 8 bit data for displaying . 3 pins for power supply , ground and contrast . 3 pin for control register , read write and enable pin and remaining 2 pin for background light .

   PIN DIAGRAM WITH FIGURE 

                           Fig(a) : Connection of Microcontroller(8051 family) with LCD 

  

Table 1: Complete LCD pin and its functions

Table 2: LCD command set instruction

2. CONNECT THE LCD WITH THE MICRO-CONTROLLER AS FIGURE BELOW  :

  - NOTE :- you can connect the data and control lines in any input / output port directly . But for

 port-0 of 8051 family you have to connect with LCD only after connecting it with resistor of 8Kohm as in figure below:- 

  Figure : Pull-up resistors connection with atmel 8051 family microcontroller

3: If you are not using the port-0 for the data lines , then you can connect  the pins of lcd to port 1,port2 and port3 because they donot need any pull-up resistors. For the figure below ,i have used port-2 as data lines. Here i have not given power supply to microcontroller and lcd because the proteus by default give the power supply and ground to each pin of lcd and microcontroller.

Fig: Proteus design sample for LCD interfacing

4. After all , we need the program to be load in microcontroller in order to interface with LCD. So for this , the microcontroller need the machine level code. And for this we have to convert the program in hex(.hex) file . i.e It represents al the code into the hexadecimal format which is understand by the microcontroller. For this i have the following code wriiten in Keil software which generate the hex file.

you can download the keil or mide software .

5. The code is given below :

               #include<reg51.h>

                         #define data P2 //initialize port 2 as data lines

sbit rs=P3^7;    // initialize port for rs

sbit rw=P3^6;    //initialize port for rw

sbit e=P3^5;     //initialize port for e 

void delay(int x)   // delay function 

    {  

int i,j;

       for(i=0;i<1275;i++)

 for(j=0;j<x;j++);

 }

void lcdcmd(unsigned char value)  // lcd command function

          {

rs=0;

  rw=0;

  P2=value;

  e=1;

  delay(25);

  e=0;

}  

 void lcddata(unsigned char value)  // lacd data function to write in lcd

 {

 rs=1;

 rw=0;

  P2=value;

 e=1;

 delay(2);

 e=0;

 }

 void initlcd()

{

lcdcmd(0x38);

lcdcmd(0x0E);

lcdcmd(0x01);

}

 void main()

 {

 int i;

 int j;

 char arr[]="my name is hari chalise";  //  which is to be written in lcd , simply change                                                                                  //  of your own wish 

  initlcd();

 for(i=0;i<=(sizeof(arr)-1);i++)

 { 

 lcddata(arr[i]);

 delay(3);

 if(i>=14) // to check if length of arr is greater than 14 then shift the display in left by 1 character so 

{    // all the character are displayed how much the character is long

lcdcmd(0x07);

       }

 }

  lcdcmd(0xC0);

                         while(1)

                {

          lcdcmd(0x18);

         delay(2);

                         } 

 }

  

6. At last the hex code format of above code is :

:100975006D79206E616D65206973206861726920EB

:080985006368616C6973650091

:10094F00E4FDFCE4FBFAC3EB9FEE6480F8EA6480FD

:10095F009850070BBB00010A80EC0DBD00010CBCC9

:05096F0004E1BDFBDE08

:010974002260

:10098D00C2B7C2B68FA0D2B57F197E0012094FC271

:02099D00B52281

:10099F00D2B7C2B68FA0D2B57F027E0012094FC266

:0209AF00B5226F

:0F09B1007F3812098D7F0E12098D7F0102098D8B

:1008F600780A7C007D007BFF7A0979757E007F1877

:100906001208D01209B1900000AF82740A2FF8E6DF

:10091600FF12099F7F037E0012094FC3E582940EE2

:10092600E5836480948040057F0712098DA3E582E4

:100936006418458370D37FC012098D7F1812098D04

:090946007F027E0012094F80F2CD

:030000000209C032

:0C09C000787FE4F6D8FD7581210208F66E

:10080000E709F608DFFA8046E709F208DFFA803EDA

:1008100088828C83E709F0A3DFFA8032E309F608C7

:10082000DFFA8078E309F208DFFA807088828C832F

:10083000E309F0A3DFFA806489828A83E0A3F608E3

:10084000DFFA805889828A83E0A3F208DFFA804CBD

:1008500080D280FA80C680D4806980F28033801094

:1008600080A680EA809A80A880DA80E280CA8033FD

:1008700089828A83ECFAE493A3C8C582C8CCC58375

:10088000CCF0A3C8C582C8CCC583CCDFE9DEE78045

:100890000D89828A83E493A3F608DFF9ECFAA9F0C4

:1008A000EDFB2289828A83ECFAE0A3C8C582C8CC1A

:1008B000C583CCF0A3C8C582C8CCC583CCDFEADE33

:1008C000E880DB89828A83E493A3F208DFF980CC95

:1008D00088F0EF60010E4E60C388F0ED2402B4048E

:1008E0000050B9F582EB2402B4040050AF23234535

:0608F00082239008507302

:00000001FF

save this code in notepad as (.hex) file name and run through proteus .

If you find difficulty  and if there are any mistake , comment are highly acknowledged. Thank you