From: Allen Mulvey <allen@amulvey.com>
To: 'Microcontroller discussion list - Public.' <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Sun, 9 Feb 2020 14:04:36 -0800
Subject: RE: [CAUTION: Failed DKIM Test][EE] IIC "backpacks" for LCD displays
Thread-Topic: [CAUTION: Failed DKIM Test][EE] IIC "backpacks" for LCD
 displays
Thread-Index: AQK6TEIE9RuJAuHLaoTfY8KWWHPpw6ZKjRiA
Message-ID: <00cf01d5df94$ead32e40$c0798ac0$@amulvey.com>
References:
 <CAFo_nNo7wo1P_7PVtnDBiJLnZ5FHexOTpQChi=gYEKu5tEP7LA@mail.gmail.com>
In-Reply-To:
 <CAFo_nNo7wo1P_7PVtnDBiJLnZ5FHexOTpQChi=gYEKu5tEP7LA@mail.gmail.com>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
Content-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: Pass (protection.outlook.com: domain of amulvey.com designates
	24.169.71.174 as permitted sender) receiver=protection.outlook.com;
	client-ip=24.169.71.174; helo=mulvey.us;
dkim-signature: v=1; c=relaxed/relaxed;
	h=from:to:references:in-reply-to:subject:date:message-id:mime-version:content-type:content-transfer-encoding;
	d=amulvey.com; s=amulvey; a=rsa-sha256;
	bh=cPYr6Leq5dBoVnrmdfhgrMZ7UdPGjhrJPEymWixNKrM=;
	b=Hbd/t0o1Y0YO7cPS0OFGXr+9KWdTEXahNdh5RGBQuoW6QKEY7GEVK8oX4sjbn3C9M
	4maFkgd8U8gZ9Ouzsw6sBmldEFP1Id2OIzhjK2b1/GlCe5SIRdDorrPtIHV6HvYl+s5
	oAmIdJGJNIbtzOPv8UgIPrsoNNmawa2e0rHtIHQ=;
authentication-results: spf=pass (sender IP is 24.169.71.174)
	smtp.mailfrom=amulvey.com; mit.edu; dkim=pass (signature was verified)
	header.d=amulvey.com;mit.edu; dmarc=bestguesspass action=none
	header.from=amulvey.com;compauth=pass reason=109
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-topics: [EE]
x-me-bayesian: 0.000000
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

Before I discovered OLED and TFT I used cheap 2x16 and 4x20 displays. All o=
f
them, I believe, had a 4 bit mode. I frequently used that because I didn't
have enough pins on the pick. Perhaps 4 bit mode would make it easier to
send just one nibble at a time.

It has been a while since I used PICs but in my Mikro-C repository I have a
folder named "LCD Over SPI"  dated 2013. I don't recall where I got it. To
the best of my recollection I never used it. I would be glad to zip it up
and send it to you. Perhaps examining it will be of some help. I think I
also have 2 of those backpacks I have never used. 8-)

Allen

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of
David C Brown
Sent: Sunday, February 9, 2020 1:45 PM
To: Microcontroller discussion list - Public.
Subject: [CAUTION: Failed DKIM Test][EE] IIC "backpacks" for LCD displays

These are offered very cheaply on eBay and purport to allow you drive ann
LCD module with just two wires.   Unfortunately the only information I can
find on line about using them is on Arduino forums where you get the
typical Arduino response "down load the library".   Since I am connecting
to a PIC that isn't much use.

I am very familiar with both LCD modules  buses and IIC bus and my worry is
this.  The LCD modules are a nine bit interface and IIC sends 8 bit data.
so how do you marry them together.

It is easy enough to envision an answer.  At its simplest you would send
two  IIC bytes to get the nine bits.  Or to send a control byte indicating
whether the subsequent bytes are commands or data.

But guessing how something works is rarely productive so help appreciated
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak                           Phone: 01663 733236
Derbyshire                eMail: dcb.home@gmail.com
SK23 7ND          web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.