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2x40 LCD (powering up?)

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Penguin7471

Sun Mar 12 2006, 07:06AM

Registered Member #71 Joined: Thu Feb 09 2006, 08:23AM
Location:
Posts: 63

Hi everyone..

I have a 2x40 LCD screen with a 14 pin connector that i found in a drawer today. Must've ripped it from something years ago... Anyway i had a look at some stores in want of a kit that provides an interface between the LCD and a computer. I want to display custom text on the LCD by simply typing it on the computer in a dialog box or something.

However, the only interface kit i found was from oatleyelectronics, and it required writing a full program everytime the text needed to be changed.

Is there a relatively economical kit that provides a program so I can just type in say, "go to school" or something, and instantly displays it on the LCD?

Bjørn

Sun Mar 12 2006, 07:40AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Most of those displays contain a Hitatchi 44780 controller. If you search for it you will find a lot of information, including schematics for connecting it directly to the printerport.

Hellmark

Sun Mar 12 2006, 09:04AM

Registered Member #189 Joined: Thu Feb 16 2006, 07:43PM
Location: Winfield, Missouri, USA
Posts: 46

if its the HD44780 (which it sounds like to me), then its fairly easy to wireup. Being 14 pin, if its the HD44780, then it doesnt have a backlight, or the backlight is on a separate part of the board (some are 16 pin, which allows for easier software control of the backlighting, with the use of a single diode.)

There are pretty much two options as far as wiring right now. A: you can use the old standby method of a parallel interface, (which is extremely easy, and I can post schematics and such for), or B: you can go with USB. If you go USB, I'd recommend doing it in this method

. For 14 pin ones, like you have, in the parallel method, you just run 14 wires directly from the plug to the corresponding spot on the LCD, nothing fancy.

Once its wired, the next part is software. On linux systems, lcdproc is a good well developed solution with support for either USB or Parallel, and for Windows, LCD Smartie is a good choice. You could also write a simple commandline app (I have some source code in C++ that would work), that would update the screen with what ever you typed in. For Macs, there is a guy who used the LCD Proc daemon, along with a custom client (LCD Proc is a client/server type setup), that works with Growl, for sending notices from any app with ease. All the above is open source software.

Right now I have a HD44780 based 4x20 blue backlit with white text LCD that I am wiring up. If I can get a double sided PCB made in the method of afforementioned link, I'd like to do that (which is actually why I was asking about the adhesive copper foil), but what I'm probably gonna end up doing is have it be parallel with a Belkin F5U002 USB Printer adapter, which will work good (as long as you get the non corded adapter, Belkin made a corded version with the same model number, and it is made in a different manner, and will not work for this). I picked up one off ebay for $5, and now just waiting on the female centronix adapter to arrive so I can wire it up, and use the adapter, or any normal printer cable.

Also, a note of interest for your LCD, is that the 40 long ones were made by hacking the 20 character displays. Only difference between a 4x20 and 2x40 is the arrangement. Basically, they'd have line one, and sat immediately next to that was the second "line", and below those two is lines 3 and 4 juxtaposed.

Penguin7471

Sun Mar 12 2006, 09:33AM

Registered Member #71 Joined: Thu Feb 09 2006, 08:23AM
Location:
Posts: 63

Wow, thanks heaps guys.

Yep its the HD44780.. I'll go for the simple, parallel method. Thanks alot for the software suggestion also, im always really lost around software stuff...

I'll let you know how it goes, whenever i get around to wiring the whole lot up.

Hellmark

Mon Mar 13 2006, 04:28AM

Registered Member #189 Joined: Thu Feb 16 2006, 07:43PM
Location: Winfield, Missouri, USA
Posts: 46

No problem man, just was glad I could help a bit.

When I get mine done up, I'll post a bit more on it too.

Edit - I recieved the Centronix adapter today. I am doing it this way, rather than using a male 25pin Dsub so that way, I can use any printer cable to connect it, or the afforementioned Belkin F5U002 USB adapter, where as most people, just hook up the standard Dsub 25pin male connector directly to the LCD.

For the most part, it is no more difficult to use a Centronix connector than hooking directly up to the 25 pin connector. Pins 1 through 14 on the centronix are treated the same as Pins 1-14 on the 25pin. The changes come in after that. Pin 15, on what would be the 25pin connector, is pin 32 on the centronix adapter, pin 16 goes to pin 31 on the centronix, and pin 17 goes to pin 36 on the centronix. Pins 18-15 on the 25 pin connector are for ground, and on the centronix, the grounds are 19 through 30. Knowing that, its drop dead easy to wire up the Centronix adapter instead, and in my opinion, you end up with a nicer, more professional setup.

Psyko

Tue Mar 14 2006, 09:52AM

Registered Member #81 Joined: Thu Feb 09 2006, 11:57AM
Location: Paris, France
Posts: 43

just have a look at

and for the software,

will match to your desires

Penguin7471

Wed Mar 15 2006, 11:17AM

Registered Member #71 Joined: Thu Feb 09 2006, 08:23AM
Location:
Posts: 63

Well its up and running...

Now i know why someone chucked it out in the first place, theres a single column of pixels that don't work, but thats fine.

I'm using LCDSmartie and it works great. Although the MBM capability is wasted since MBM5 doesnt support my motherboard...

Thanks for all the info!

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