Yes, it will drive all 16 characters fine but the 16 characters are not
in sequential order when you write to the display.  The first 8 characters
are in sequence, the last 8 are offset by 40 characters.  The Densitron
16x1 line display is organized as 16x1 line in memory.  The surplus LCD display
you now have is organized as a 8x2 line display with a 16x1 line 'glass'.

  After you send your first 8 characters, send the display a C0h instruction
(not a character!), this will position the cursor at the 9th position for
writing.  After you display your next 8 characters, or anytime you want to
return to the first character, send the home command.

Surplus LCD displays are a great value, but this memory organization is
something to watch out for!  Also look out for extended temperature displays
- you cannot see the characters without driving the contrast pin negative.
Also, if the display is not supertwist, be careful of the viewing angle.

Dave


At 09:19 PM 12/1/96 -0500, you wrote:
> 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
>
>----------------------------------------------------------------
>Henry Carl Ott   N2RVQ   | talk/chat  carlott@204.74.7.186
>carlott@interport.net    | http://www.interport.net/~carlott/
>----------------------------------------------------------------
>"A day job...in an office? My worst nightmare!"-Ticknophobia
>
>
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