[SOLVED] LCD 4 bit interfacing doubts .

[gravity123]

I am trying to interface lcd in 4 bit mode ..
I stucked in where the initialization
According to data sheet ,what hex value give for 4bit mode after power on the LCD.
I googled and searched in edaboard most of the people give it value 0x38 three times with delay
i think it is 0x28 for 4 bit mode (2line)
please guide me ?
see the algorithm

Thanks


i am initialising

LCD ON
delay(); 15ms
command instruction giving 0x28 //4 bit mode
delay(); 4.1ms
command(0x28);
delay(); 100mirco secod
command (0x28)

is it correct ?
why gives 3 times this ?

 

[nandhu015]

As the lcd module power up it should be initialized in 8 bit mode (i.e. 0x38). After initializing in 8 bit mode then it can be changed to 4 bit mode (i.e. 0x28).

Here is the sequence

Wait for 15ms.
command 0x38
wait for 4.1ms
command 0x38
wait for 100 us
command 0x38
wait for 100 us
command 0x28 //4 bit mode

Hope it is clear now.

 

[gravity123]

thanks cleared
why does, this is necessary ?
above image shows 000011 what is that ?
please explain with algorithm ..

 

[Venkadesh_M]

That is 0x30 to the command register.. that is the initialization in the Hitachi driver.....

 

[gravity123]

That is 0x30 to the command register.. that is the initialization in the Hitachi driver.....

Confusing ?
000011 is 0x30 ? :sad:

30 hex is equal to 00110000

then how
help me ?

bit order in reverse order ? How ?

 

[Venkadesh_M]

you are correct
it is

  0  0  1  1  0  0  0  0
 D7 D6 D5 D4 D3 D2 D1 D0

look at the top of the table as well...
But You are not going to use the D3 to D0...
In 4 bit mode you are going to use higher 4 bits only the remaining nibble will be send as second instruction...
look at the table after sending 0x20 it is initialized 4 bit mode........
blog.vinu.co.in/2011/06/4-bit-interfacing-of-16x2-lcd-display.html‎

 

[gravity123]

oh thanks its my fault
i mistaken ,considered, taking RS and RW as digit 0 and digit 1 respectively