Importen informatin about using lcd's 4x20 with LiquidCrystal and HD44780 ! !

Other Hardware Displays
1

I have seen a lot of members have problems with lcd displays with 4x20 char, this is because the HD44780 can only handle 1 or 2 lines.Then you have to set it up as a 2x40 char display.
lcd.begin(40,2);
then you use the setCurser as follows.
Line 1 (0-19,0)
Line 2 (0-19,1)
Line 3 (20-39,0)
Line 4 (20,39,1)
Hope this kan help som of the members.
Regards
Erik

2

Personally I think the libraries fix this in the background (never had this problem).
Which library are you using?

3

... this is because the HD44780 can only handle 1 or 2 lines ...

You are confusing the number of rows of characters on the display with the number of lines of memory as perceived by the LCD controller.

With very few exceptions (some 16x1 displays) the display must be instructed to deal with its display memory in terms of two lines. As Rob said, the library takes care of the rest (except for the remainder of the 16x1 displays).

For a complete explanation follow the LCD Addressing link at Don's Collected Technical Information.

Don

4

You are both right, I am using the last version of LiqidCrystal, I have not testet it
with the right parameters before, because I have read many members have problems with
But now I can teste som follows and it is working in the new version.
lcd.begin(25,4);
then I used the setCurser as follows.
Line 1 (0-19,0)
Line 2 (0-19,1)
Line 3 (0-19,2)
Line 4 (0-19,3)
it is working correct.

Regards
Erik