can not read data from ks0108 lcd

[abbas1707]

read data from lcd

i was playing with ks0108 lcd on proteus using 89c51. i am able to write data,fonts and images to lcd . but i cant read data from display RAM.
here is code for reading data from lcd

Code:


#include <reg51.h>

sbit rs=P3^3;
sbit rw=P3^2;
sbit en=P3^1;
sbit cs1=P3^5;
sbit cs2=P3^4;

void delay()
{
   int k,l;
   for(k=0;k<3;k++)
      for(l=0;l<50;l++);
}
void sendCommand(unsigned char val)
{
   P1=val;
   rs=0;
   rw=0;
   en=1;
   en=0;
}
void sendByte(unsigned char dat)
{

   P1=dat;
   rs=1;
   rw=0;
   en=1;
   en=0;
}
void readByte()
{
   
   P1=0xff;
   rs=1;
   rw=1;
   delay();
   en=1;
   delay();
   en=0;
   P2=P1;
}

void main()
{
     while(1)
     {
      cs1=0;
      sendCommand(0x40);
      sendCommand(0xb8);
      sendByte(0xf4);
      sendCommand(0x40);
      sendCommand(0xb8);
      readByte();
      readByte();
   }
}

please help me solving this problem

 

[jit_singh_tara]

read data from ks0108

well friend , i see a error in read routine in your program ,

try this logic :
**********************************************
p1=0xff;
rw = 1;
rs=1;
en = 1;
pause 2ms;
en = 0;

pause 2ms;

en = 1;
temp = port1;
pause 2ms;
en = 0;
value = temp;
*********************************
return;

and do tell me whenf it worked

Added after 11 minutes:

no need to call read byte two times !

Added after 2 minutes:

i think you misinterpreted datasheet , it says while reading a data byte , first the data from ram comes to buffer so you have to add en = 1 and en = 0 one more time to get it to port something like it . that makes it 2 times within 1 routine.

 

[abbas1707]

lcd ks0108 cant read

gr8 jit_singh_tara!!!
Thanks for helping

i always sleep while reading data sheets