lcd interfacing

[SNEHAL]

in a lcd to 8051 interfacing diagram,what are the directions of the control lines that start from RS,R/W,E.?

 

[barathbushan]

are you a VTU student ??

 

[SNEHAL]

I don't get u sir.My discipline is Electronics and telecomm.

 

[barathbushan]

see if you can understand this http://www.lcdinterfacing.info/lcd_8051.jpg

 

[SNEHAL]

i've seen this schematic before.but the lines that emanate from RS,R/W,E .what cud be their possible directions???

 

[barathbushan]

for an LCD module

rs- this is used to select the command mode or data mode , the signal goes to this pin from the 8051

RW=when set to' 0' , data is read from the lcd and when set to '1' data is sent to the lcd
so it is a bi-directional connection to the 8051

E=1 to operate the LCD , this pin is controlled by 8051 , so the direction is from 8051 to this pin

 

[SNEHAL]

thank you sir! how does a lcd function in its 4-bit mode?

 

[barathbushan]

in 4 bit mode , both the command and data are sent in strings of 4 bits
so Mask the lower 4-bits , then send it to the port , and when enabled by another pin , lcd accepts the 4 bits and displays it .
next mask the upper 4 bits , send it to the port and enable it .

Do this for both command and data modes