LCD Display Addresses Help

[Suraj143]

In a 16 X 2 LCD the display addresses starts like this.

00--------0F = 1st line - 16 locations
40--------4F = 2nd line - 16 locations

One article it says there are 80 display locations, 40 on each line.

So where are the other balance addresses?

If I add another 24 locations to the first line to become 40 addresses, the last address will stop from 27.
So the full address range will be 00--------27 (40) locations.

So where are the others 28-------3F???? Because second line starts from 40h.

 

[Nigel Goodwin]

The screen is a 'window' 16 characters wide, sat on a 40 character wide buffer. You can scroll the window left and right along the buffer with commands, check the datasheet.

 

[colin mac]

28 - 3F don't exist
It's 0H - 27H first line and 40H - 67H 2nd line

 

[Suraj143]

28 - 3F don't exist
It's 0H - 27H first line and 40H - 67H 2nd line

Hi thats what I need.Thanks for that.

 

[AtomSoft]

Never Mind: I miss read the question

 

[colin mac]

Yes but 28 to 3F don't exist on a two line display.
http://home.iae.nl/users/pouweha/lcd/lcd0.shtml#_2_line_displays

 

[CCD]

LCD addresses

>In a 16 X 2 LCD the display addresses starts like this.

>00--------0F = 1st line - 16 locations
>40--------4F = 2nd line - 16 locations

>One article it says there are 80 display locations, 40 on each line.

yup, 40 location on each line, since internal buffer is 40 char long, all these 40 locations per line are used when u use an LCD with 40x2 or 20x4 char.
20x4 LCD is like a folded 40x2 LCD. So, the location of the third line starts where the location of first line ends, same is with the 2nd and 4th line.
This address format is adopted as they don't have to manufacture a different controller for 16x2,20x2,40x2 or 20x4. same controller+buffer works for all. and it makes life of programmer easy as he doesn't have to remember different addresses with different size of LCDs