From: "Richard Webb"
Subject: Re: Help: using (connecting) 4bit LCD on parallel port
Date: Mon, 18 Nov 2002 12:19:14 -0000
NNTP-Posting-Date: 18 Nov 2002 12:17:47 GMT
X-Newsreader: Microsoft Outlook Express 5.00.2919.6700
There's a great tutorial of how to use LCD's from the UK magazine 'Everyday
with Practical Electronics', find it at:
"Rich Webb" wrote in message
> On Sat, 16 Nov 2002 20:43:07 GMT, "Te" wrote:
> >Let me start with- I'm not very technical, so if you can help, and are
> >willing to help - I'll need any explanations in simple terms :) Also if
> >can, PLEASE PLEASE PLEASE email any response to me- I really want to make
> >this work- and don't read the groups too often.
> Then perhaps you'll not see the response but I prefer to answer public
> questions in public.
> >I purchased a 2x20 LCD display from bgmicro.com (the lcd1022), which has
> >equiv. controller to a hd44780. It has 10 pins connection pins (the link
> >a spec sheet is below), and from what I understood by the document on
> >bgmicro's site, its a 4-bit interface (since its only using datalines 4-7
> >only, and not 0-3). So by looking at a schematic for an 8bit lcd, I
> >the pins from one lcd to the other (ie: vcc to vcc, d4 to d4, rw to rw, e
> >e, etc), and connected it to my parallel port. But all I'm getting is
> >jibberish on the display :( I'm using a program called Smartie-LCD for
> >display simple computer info (cpu temp, fan speed, etc)
> From a quick look at the LCD Smartie page, it looks like it is written
> to support 8-bit interfaces.
> "Ok, i had some ppl from sweden who had 4 bit LCD's. One of them told me
> that you could mod your 4 bit LCD to a 8 bit by soldering wires directly
> to the chip. the codes next to the pins indicate tell you what wires you
> can use in the above circuits Beware not to solder anything wrong!"
> Interfacing to this type of display with only four bits is pretty
> common. Basically, the module starts from power-on reset in 8-bit mode.
> Wire the lower 4 bits to ground and command it via a little dance to go
> into 4-bit mode -- which, conveniently enough, only requires you to use
> the upper four bits. Using fewer pins is usually A Good Thing,
> especially when interfacing to microcontrollers, which is why
> nibble-wide modules are sold in addition to "regular" byte-wide.
> There's no intrinsic reason why the software couldn't be written to
> initialize and operate the display in 4-bit mode. However, until it is,
> it won't.
> BTW, there's a copy of the Optrex manual available online at
> Hang on to your 4-bit module (or trade it to another hobbyist) but
> you'll need an 8-bit module to use with that application. Also, with
> respect to the note above about soldering directly to the pins on the
> controller -- be careful that the pins are not also connected to ground.
> If you decide to go that route, you'll probably need to lift them from
> the pads and solder directly to the pins.
> Rich Webb Norfolk, VA