thanks to Chip Weller, Mike and others who helped.
I hoped that this is the case (easier one).
Ivan Cenov

-----Original Message-----
From: Mike Keitz <mkeitz@JUNO.COM>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: 02 Септември 1998 г., сряда 16:42
Subject: Re: Hitachi HD44780


>On Wed, 2 Sep 1998 15:19:24 +0300 Ivan Cenov <okto7@BOTEV.TTM.BG> writes:
>>hi,
>>i have to drive one LCD module with Hitachi HD44780 compatible chip
>>inside it.
>>My question is for E (enable) signal.
>>1. Should it to be continuous (as E (f2) with motorola's 6800, hc11) ?
>
>No, it must be pulsed with each read or write.  It isn't a clock, it's a
>chip select.  When the E signal is low, the data on the other pins of the
>LCD is don't care, allowing them to be shared with other hardware.  The
>original intent was to connect the LCD to a VonNeuman processor's 8-bit
>bus.  When E is high, the LCD inputs or outputs.  If you are polling the
>status bit to see when the LCD is busy (not recommended for beginners,
>put in lots of delay instead), E must pulse low then high in order to
>latch a new copy of the busy bit.  If you just hold E high while the LCD
>is busy, the data output won't change back to not busy when it is not
>busy.
>
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