LCD_8bits

aymen · ‎2012-12-12

Posted on December 12, 2012 at 10:09

I am trying to use an LCD HD44780 (2X40) with STM3210C-eval. I want to configure it for 8 bits mode.

#re-inventing-the-wheel

aymen · ‎2013-01-02

Posted on January 02, 2013 at 10:10

finally, it works with 4bits-mode.

thank you for yor help. :)

jj2 · ‎2013-01-02

Posted on January 02, 2013 at 17:29

Glad for that - congrats!

It would be most helpful to the (exhausted) yet interested others who read this - if you'd detail just how you finally succeeded. Suspect (as always) that ''initialization'' was key - and that once this was solved you could work out the dual nibble, character entry details...

aymen · ‎2013-01-08

Posted on January 08, 2013 at 16:28

I increase the time of delay (<<2) in lcd_init .

I Minimize the cable length between the module and host MPU. (Recommended max. length 30 cm).

also I find that the lcd need negative votlage Max(VDD-Vo)=13.

jj2 · ‎2013-01-08

Posted on January 08, 2013 at 16:42

Glad you persisted - got it working.

Very early on - you were advised about likely need for negative voltage @ Vo pin.

However - we know of NO 2 line, character display - that requires up to -8V (wrt gnd) on Vo. Suspect yours operates quite well w/ -2, -3 max @ Vo.

So long as you follow the initialization delay details outlined here (w/real values) - you should be ok. The very first initialization codes require unusually long delays - after those things become more reasonable.

When using 4 bit mode - always advisable to periodically, ''re-initialize'' the Lcd - just in case noise or power issue has caused the Lcd to become, ''disordered.''