In response to James Paul [mailto:jamesp@intertex.net]

>  First let me say that the choice of 8 bit vs 4 bit is
> strictly a matter
>  of personal taste and/or IO pin limitations. Also, in some
> cases, there
>  are LCD displays out there that are 4 bit only.  I have some
> of these and
>  this is the main reason I use 4 bit interface so much.

Yes, most LCD can be used in 4 or 8 bit mode without any limitations.
I don't know of any 4bit only LCDs.

>  When I power up the LCD/uC combination, The uC
> initializes first.
>  Then, when the program starts running, it initializes the
> LCD.  It does
>  this starting in 8 bit first.  I send this 3 times.  After
> that, I change
>  to 4 bit, and away we go.  If for some reason, the uC
> freezes or loses
>  it's place, the watchdog timer will reset the uC and again
> reinitialize
>  the LCD in the same manner as before.

This is the scenario which i have described.
Furthermore i assume the uP is reset after he was sending the first 4bit of
a command.
In this case i'm not sure that the LCD is interpreting the next nibbles in
the right way.

>  As long as I can in itialize the LCD and get it to do what I want, I
>  don't really mind a slightly lengthy and somewhat illogical
> initialization
>  sequence.

I agree with you for the 8bit mode, for 4bit i'm not sure.

Thanks for your long answer,
Frank

GSP Sprachtechnologie GmbH
Frank Wollenberg
HW-Entwicklung
Tel.:   +49 (0)30 769929-78
Fax:    +49 (0)30 769929-12
eMail:  f.wollenberg@gsp-berlin.de


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