NHD‐0220DZW‐AY5 loosing columns

[tseyfarth]

Hello all,

I am using an Atmel ATMEGA32A to drive an OLED -  NHD‐0220DZW‐AY5 (2x20 and 4x20).  The same code is also used to drive an LCD  NHD‐0220GZ‐FL‐GBW again, either a 2x20 or 4x20.  With the OLED, over time, characters are lost. Seems to be on the left side of the screen.  It takes several weeks for this to happen and only happens with the OLED.

For code development we use BASCOM by MCS Electronics.   
The enclosed screen shot shows the display - the top line is missing the "W"  for "Welcome"; the second line is missing the "T" for "Titan".  Over time, it gets worse with more characters missing from the left side.

Can anyone suggest what is wrong and how to fix it?
Thank you,
Tim

[Saurabh_B]

Hi,

This situation often occurs because of a timing error in the code, You mentioned you are using the same code as the NHD-0220GZ-FL-GBW, while they have the same commands, the OLED does require more time between instructions.

[tseyfarth]

How much time? 
Since you do not list the driver in the docs, maybe listing it *and* noting that t Time needs to be added between instructions would be beneficial.

Tim

[Saurabh_B]

Some instructions have a max execution time of up to 600us, while the write cycle has a minimum of 500ns. For the LCD display it takes a max of 37us for some instructions.

NHD-0220DZW-AY5 Datasheet