Writing to off-screen and reading it back never occured to me.  It is a =
good idea.  I'll play with initialization of the pic and the lcd a =
little bit more, see if I can fix it at the source.  If not this idea =
seems good to work.

thanks for the tip,=20

Omer


-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Nigel Orr
Sent: Monday, July 14, 2003 5:55 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [EE]: NPN Transistors


> Should you choose to put a band-aid over it: I don't think
> you need to turn the contrast off. You should be able to
> read/write so rapidly that a user wouldn't really see it.

On the 44780-type drivers, are unused data locations implemented?  I
presume they are, so on a 16 character display, you could write to and =
read
from character 17 as slowly as you wanted without it being visible- is =
that
correct?

You could also write and read with the display turned off, but I'm not =
sure
that being able to correctly read a character is a guarantee that the =
LCD
has initialised properly.

Oh, and I only glanced at the transistor circuit, and now I've deleted =
it,
but ISTR that the NPN was the wrong way round.  It also wouldn't have =
given
the full range of 0-5V, which is apparently needed for some displays =
(some
have acceptable contrast at close to 0V, some at close to 5V, AIUI.

Nigel
--
Nigel Orr, Design Engineer                 nigel@axoninstruments.co.uk
Axon Instruments Ltd., Wardes Road,Inverurie,Aberdeenshire,UK,AB51 3TT
               Tel:+44 1467 622332 Fax:+44 1467 625235
                   http://www.axoninstruments.co.uk

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