4x40 Inquiry

I need a 40x4 display.

The CFAH4004A-YYB-JP (http://www.crystalfontz.com/products/4004a/index.html) seams good. But could I get some infomation on how to hook it up. A web page or anything. Or is it as simple as the pdf spec says, and just use the normal paralel lines? It preferably needs to be usb. So do serial/paralel to usb adapters work well?

Also if its paralel how fast can the display update? Would there if a differance between it and the high speed serial ones?

I already have a serial lcd (4x20) and I like its features. As this is not a serail one, can I still controll the backlight with software? (I Asume that its too simple to have startup text and the like?)

I would prefare to use cryatalfontz as I like the company, but if anyone knows of a good suplyer of a 4x40 with a black on blue backlight display, non-flicker, fast refresh, seral interface and an easy way to hook it up. I would be very greatfull. I'm begining to think the perfect display does not exist, hence asking about this green 40x4.

Much Thanks
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New member
40x4 LCD

There is plenty of information on how to hook up a HD44780 type LCD to your computer's parallel port. Here is one option:

If you have experience with programming, you can do many things. If not, there are many free example programs you can use like this one, that outputs a text file to the LCD: LCD Print
The text is stored in the same DIR by the name Hello.txt

I'm not quite sure about the USB converter, however I'm sure there is information out there somewhere.

Search google.com for much more info on controling an LCD through your parallel port, etc.

Is parallel faster? Generally yes.
Can the backlight be controled with software? Generally no.

Perfect LCD? If your really rich you can have one custom made. ;)

Hope this will help you out!



New member
The schematics for a 4*40 lcd are slightly different.. A 4*40 is basically two 2*40 displays. So there's a second enable pin and some other pins on a 4*40. I haven't got those schematics (sorry) But look around the internet and you'll find them.. Or if someone has them he/she might post them here? :)


New member
Second Enable

Yes you are very correct. I forgot to include that... :)

The 40x4 display has a 16 wire interface where as the 20x4 has a 14 wire interface. The difference is the second Enable line, 40x4 displays have two Hitachi HD44780 controler chips on them. On standard LCDs, pins 1-7 are data, pins 9-11 are control, pin 12 is contrast adjust, pin 13 is ground, and pin14 is 5 volt power. If there are two controler chips on the LCD ie. the 40x4, pin 15 is also a control line. All the data and control lines can be wired directly to the parallel port of a computer.