Hi

On 1*16 displays using only one HD44780 (no additional 44100), multiplexed
at 1:16, the DD RAM address for the last 8 characters begins at 40h. It is
because the HD44780 sets up the display as 2 lines (2*8), when using 1:16
multiplexing.

You were right. It had something to do with the dutycycle (strange the FAQs
don't mention it?).
I guess you have to change the source code, to fix the problem :-(    The
LCD-modules with only one controller are the far most common.  If you write
to both adresses (9h and 40h), both types of displays will work.

-Jacob Blichfeldt


> Hi folks,
> Quick question (maybe).
> I'm trying to drop in a surplus replacement LCD display (1x16 hd44780
>controller) into an existing PIC project, and I'm having a problem.
> The original display (a densitron lm2015) works fine, but the new display
>(noname, but suposedly supertwist) only displays the first 8 characters.
>They both have a hd44780 controller, but I notice that the densitron also
>has an additional OKI row driver.
> Will the hd44780 drive 16 character without an additional row driver? Or
>did I some how wind up with some crippled 8 character displays (never
heard
>of it before). I'm guessing it might have something to do with the duty
>cycle, but I don't want to touch the working source code and have burn new
>chips.
> I can't find any references to this problem in any of the numerous online
>LCD FAQs.
>
>Thanks in Advance.
>
>
>PS&FWIW the new displays seem to have a six o'clock viewing angle :-)
>
>carl
>
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>Henry Carl Ott   N2RVQ   | talk/chat  carlott@204.74.7.186
>carlott@interport.net    | http://www.interport.net/~carlott/
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>"A day job...in an office? My worst nightmare!"-Ticknophobia
>
>

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