LCD HD44780 Not Working

[stoogicide]

Hi Guys,
Having a problem with my lcd. FINALLY managed to finish soldering it today and plugged it in. The LCD backlight is on and there are 2 lines out of 4 which have all the little character tiles lit up black (little black squares made up of the pixels).

I've triple checked the wiring. I used this diagram to do it seeing as it only had 16 things to solder stuff onto.
http://www.square-man.com/ebay/LCD/lcd_schematic.gif

I've got the 5.4 version of the program. Running it through a parallel port to USB cable. Do have a spare parallel port to parallel port cable and have tried using this but to no success. Am running win7 x64.

Please Help. I don't know if i need drivers or if i need to change settings as far as ports go or what.

Can up load pictures if required.

Thanks.

[mattcro]

If you're using a USB to parallel printer adaptor, there's bad news for you... these do not work for LCDs because they only emulate the printer functions of the parallel port. They don't allow software like Smartie to directly control the port pins, which is what you need for the LCD to work.

The only way to connect an LCD with a parallel port is to get a PCI card that provides a real parallel port. Of course, that doesn't work for a laptop.

There are a couple of methods to connect an LCD via USB. Nick has posted details and a plugin for his FDTI USB adapter here: http://forums.lcdsmartie.org/viewtopic.php?f=11&t=1540 and you can also use the USB2LCD adaptor here http://www.harbaum.org/till/lcd2usb/index.shtml (there are complete kits on ebay and at http://www.lcdmodkit.com ).

[stoogicide]

Thanks for that, i'll have a look into it. However i'm not even sure the screen works at this point. So i've got the parallel port cable out and plugged it into the parallel port in the computer (an actual db25 port). Cept it still didn't work. I got the same result. Any ideas on how to test/what settings to use cause I've tried all i can think of and that i've found.

Want to get what i have working before i start experimenting/improving

[caesar]

plugged it into the parallel port in the computer (an actual db25 port)

Good. Now you have to install port95nt for win xp or inpout32 for vista/seven http://forums.lcdsmartie.org/viewtopic.php?f=5&t=1799

Let us know!

[stoogicide]

Ok downloaded and put the drivers for the x64 version into the folder. Now i have the same thing but with one character tile flashing. Can't seem to get it to work despite any program settings. Any that i should be using or you recommend i try. Have the Hd... one selected and the port is ltp1. Tried LTP2, 3 and 4 as well as $278 and $378 but no luck. Any ideas as to which to use?

Not entirely sure but how do you test if the screen is stuffed? Cause i'm starting to think it might be.

Thanks

[mattcro]

If the LCD shows solid blocks on every other line (like top and third lines) then it's probably ok. That's the internal self-test, but there may still be a problem with the interface pins. The blocks will disappear when you start writing data to the LCD.

Some people have had a lot of trouble getting parallel port LCDs to work properly, but for others it works fine. Double-check your wiring, and make sure that you have at least 1 ground wire connected between the LCD and parallel port.

[stoogicide]

Thanks for your responses. Sadly it turns out the parallel plug I bought was damaged. As a result, I've got to resolder another one.

Have a question regarding connecting it to a computer. Would one of these work? Just thinking ahead to when i upgrade as modern boards don't have a parallel port, but they do have 26pin sockets.
http://cgi.ebay.com.au/Parallel-Port-Ca ... %26ps%3D54

Thanks

[caesar]

You could even cut the cable from the bracket mount and solder it internally (or use the same type of connector on the other end and route the cables properly, that same type of connector can be used on the LCD/VFD end too).
If the mobo has a connector for parallel port then it should work.