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aymen
aymen
Associate III
December 12, 2012
Question

LCD_8bits

  • December 12, 2012
  • 33 replies
  • 3651 views
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
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    jj2
    jj2
    Associate
    January 2, 2013
    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
    aymenAuthor
    Associate III
    January 8, 2013
    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
    jj2
    Associate
    January 8, 2013
    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.'' 

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