Newsgroups: comp.robotics
Path: cantaloupe.srv.cs.cmu.edu!das-news2.harvard.edu!news2.near.net!news.mathworks.com!udel!gatech!swrinde!pipex!uunet!psinntp!micro2!schulka
From: schulka@pb.com (Kenneth A. Schulz)
Subject: Re: Need LCD wiring - 16 wires
Message-ID: <1994Nov15.202218.10776@pb.com>
Organization: Pitney Bowes
References: <NAHSHON.94Nov13120343@dan.haifa.ibm.com>
Date: Tue, 15 Nov 1994 20:22:18 GMT
Lines: 35

nahshon@dan.haifa.ibm.com (Itai Nahshon) writes:

>I found 40x4 LCD displays which come with a 16 wire connector. It looks
>like the wiring is different from the "standard" 14 wire connection
>(which is described on the LCD faq). The chips on the back are similar
>to another 20x2 display which has the standard 14 wire connection (just
>more chips).

>Thanks in advance,

Densitron alone uses several different pinouts for their modules.  The 
most reliable way I know to determine the pinout is to continuity-check
from the controller chip.  The Hitachi HD44780 (in PQFP) pins are numbered
counterclockwise from the beveled corner.  The pins which are brought out
to the connector directly are: 
  23       Gnd
  26 - 30  Vdisp
  33       Vcc
  36       RS
  37       R/~W
  38       Enable
  39 - 46  DB0 - DB7, respectively

Since the '44780's display RAM is only 80 bytes, a 4x40 display needs two of
them.  All the signals are wired in common except the enables, which are
brought to the 16-pin connector individually.  One will enter characters in
lines 1 and 2, the other in lines 3 and 4.  Erasing, cursor positioning, etc.
must likewise be done with commands addressed to each half of the display.

Good luck.

-- 
Kenneth A. Schulz			Phone: (203)924-3296
Technical Advisor			Fax:   (203)924-3409
Pitney Bowes Technology Center		e-mail:schulka@pb.com
