Need major help connecting 4x20 character lcd

[hanleychan]

Hi,
I recently bought this and received it in the mail today
http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=3807118125&category=26206&sspagename=STRK%3AMEBWN%3AIT&rd=1

I have no idea how to connect this to the computer at all. Don't even know where to start. The seller told me that I could connect it but I had to make my own cable. Does anyone know if there are some very simple step by step guides on how to do this.

thanks

[Serraph]

Here are some LCD links:

http://forums.bit-tech.net/showthread.php?threadid=5582
http://www.gideontech.com/guides/lcd/
http://www.overclockers.com.au/~mwp...tup-hd44780.htm
http://www.icehw.net/article.asp?id=104
http://www.overclockers.com.au/techstuff/a_diy_lcd/
http://www.myrolypoly.com/lcd_project/lcd_project.html

The circuit design may differ slightly depending on 1) if you want to use potentiometers to control contrast/backlight 2) if you want a fixed level of contrast/backlight 3) if the lcd has a backlight at all 4) etc

It's pretty easy to do actually. All you're really doing is soldering the wires from the lcd pins to the db25 printer cable.

For the software:
http://www.crystalfontz.com/softwar...trol/index.html (free and easy to use; can display MBM5 and other computer info)

http://www.lcdc.cc/index.php ($17.50; alot more functionality than CC)

http://jalcds.de (my favorite, not recommended for beginners)

[hanleychan]

Basically from what I read am I susposed to cut off the centronics end of the printer cable and connect pins 1 to 14 on the lcd to the correct wires on the printer cable. Then connect pins 15 and 16 to a molex connector for the backlit power?

[Cyrix_2k]

Originally posted by hanleychan
Basically from what I read am I susposed to cut off the centronics end of the printer cable and connect pins 1 to 14 on the lcd to the correct wires on the printer cable. Then connect pins 15 and 16 to a molex connector for the backlit power?

You got it:D Just be careful with the power. EL backlight require an inverter while LED backlights usually require a resistor.

Also, before you plug it in, check all connections for continuity with multimeter.

[Serraph]

Originally posted by hanleychan
Basically from what I read am I susposed to cut off the centronics end of the printer cable and connect pins 1 to 14 on the lcd to the correct wires on the printer cable. Then connect pins 15 and 16 to a molex connector for the backlit power?

That or you could just buy some wire and make your own cable. I could never find one of those older printer cables that could be taken apart so I just wired my own up and used heatshrink to contain the wires.

Here's links for the connector and housing:
http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?prmenbr=91&prrfnbr=1437&cgrfnbr=501&ctgys=
http://www.jameco.com/cgi-bin/ncommerce3/ProductDisplay?prmenbr=91&prrfnbr=688&cgrfnbr=501&ctgys=

[hanleychan]

Yeah I couldn't find any printer cables like that ethier. I looked at future shop, staples, and radio shack and all they seem to have are the cables with molded connectors

[{BC}Helix]

you should look at your local electronics shop, if you have soldering skills you can just buy a blank male connector for the parallel port and solder your wires onto that. here are some pics of the way i did it that might help you hook your's up or give you some ideas. I followed the guide over at gideontech http://www.gideontech.com/guides/lcd/
you can see how i hooked it up to my power supply too.

http://www.clanbbw.com/publicimg/data/images/picture1.jpg
http://www.clanbbw.com/publicimg/data/images/picture2.jpg
http://www.clanbbw.com/publicimg/data/images/picture3.jpg
http://www.clanbbw.com/publicimg/data/images/picture4.jpg

[hanleychan]

based on the table from http://www.myrolypoly.com/lcd_project/lcd_project.html it says that pin 15 and 16 are for led + and led - for the backlight. I was thinking of using a molex connector from a case fan would this work? Also which wire is the negative and positive (red or black)

thanks

[{BC}Helix]

yes, and a molex power connector for +5 and -ground would work. Red is + and Black is -

[hanleychan]

Got a problem. For some reason after I connect the lcd to the parralel printer port it doesn't seem to work. I get no picture on the lcd. I soldered the wires from the printer cable directly to the lcd. The led seems to work though when I plug in the power from my power supply. Could it be a contrast problem? I am pretty sure I got the connections right because I checked it over. I think pin number 3 on the lcd is for contrast adjustment but the table leaves out pin number 3. What should I do?

I am using this table
DB25 connector Pin Number LCD Pin Number LCD Pin Description
1 6 Enable
2 7 Data 0
3 8 Data 1
4 9 Data 2
5 10 Data 3
6 11 Data 4
7 12 Data 5
8 13 Data 6
9 14 Data 7
14 5 Read/Write
16 4 RS
25 1 Ground
13 2 +5V

[hanleychan]

nvm. Never read the instructions properly. I'm susposed to connect a wire from pins 3 to 1 on the lcd to fix the contrast. Can I use anywire to do this like speaker wire?

[hanleychan]

I need help again. I don't know what to do. I soldered everything from that tablle onto the lcd and connected pins 1 and 3 together and it still doesn't work

[{BC}Helix]

i think you need to put in a potentiometer to vary the contrast, (you can also put one in for brightness too). what guide did you follow? I suggest you look at this schematic and see what you could have done wrong with your wiring.

http://www.clanbbw.com/publicimg/data/images/LCD.jpg

[hanleychan]

I was looking at this one
http://www.overclockers.com.au/~mwp/cc/guides/setup-hd44780.htm

it says that I can solder a wire from pin 1 to 3 to fix the contrast.
I tried attaching a molex connector to pins one and two on the lcd. red on 2 and black on 1 and it seems to show the first and 2nd column all filled with black squares. This is good or not?

[{BC}Helix]

yes! thats exactly what you want to happen, two lines of squares. All you need to do now if find a program to power the LCD

[hanleychan]

I connected everything and powered on the computer. There was a spark on a wire near the lcd that scared the living crap out of me then the computer shut it self off. I was so scared that I fried the whole computer because I could power the computer on for a while after this. It seems to work now though. I don't think I shorted the lcd becuase it still shows the 2 rows of filled squares when I power it on and the backlight still seems to work. Wierd.

[shard]

dont worry it probaly it just was some condensation on the link

[hanleychan]

I plugged everything in and it shows the 1st and 3rd line of the boxes filled in, but its not working properly with the programs. I am trying to use this program

http://www.crystalfontz.com/software/crystalcontrol/index.html

the stuff don't display properly. All i get are some boxes that are filled completely in black. Have I damaged my lcd?

[hanleychan]

Heres some of the gibberish that its displaying when I use that program to display the date and hd space
http://members.shaw.ca/hanleychan/lcd.JPG

I hope I didn't break my lcd

[{BC}Helix]

hmmm, thats odd. you might want to try a different program. the one i use is called JALCDS if you use that you're going to have to get a file file called DLPORTIO.DLL, you can find it if you search on google. anothing thing might be your baud rate. can you find anything if that program about that?

edit: also check what setting your parallel port is at in the BIOS

[hanleychan]

Just checked bios and it says
onboard parralel port: auto
Parallel Port Mode: ECP
Parallel Port IRQ: Auto
Parallel Port DMA: Auto


I went to the Jalcd site but it wasn't in engliish :(

Edit: Just downloaded Jalcd and when I run it all the boxes on the lcd get filled up and it stays that way until I turn off my computer and on again.

[{BC}Helix]

ok try changing the BIOS settings to the following and see if anything happends

Onboard parallel port 378/IRQ7
parallel port mode: SPP

That 378 is important

[hanleychan]

No good its the exact same :(

under onboard parallel port I chose 378h
parallel port mode : SPP
Parallel Port IRQ: 7


this is so frustrating. I don't think my wiring is wrong but I guess I'll double check it again just to make sure

[{BC}Helix]

Yeah, thats the only thing i can think of at this point, the wiring. but do that double check and see if you messed up somewhere, also check your soldering points

[hanleychan]

based on thiis
DB25 connector Pin Number LCD Pin Number LCD Pin Description
1 6 Enable
2 7 Data 0
3 8 Data 1
4 9 Data 2
5 10 Data 3
6 11 Data 4
7 12 Data 5
8 13 Data 6
9 14 Data 7
14 5 Read/Write
16 4 RS
25 1 Ground
13 2 +5V

All of the wiring it correct. I just tried connecting the lcd to another computer and its still the same thing so it shouldn't be a computer problem. The soldering points seem to be fine. Can't think of anything else to do. I've tried all different settings and come up with nothing

[pik4chu]

btw the table that your using does not match the schematic that helix posted btw.

[hanleychan]

I found the table on http://www.myrolypoly.com/lcd_project/lcd_project.html so it should be correct hopefully. I used the table becaues its a lot easier to understand for me since I don't have much knowledge of electronics

[{BC}Helix]

well, if you never find and remedy the problem your currently having with the way you now have it set it up, try using the schematic i posted earlier with the parallel port connector and potentiometers. i've hooked up two LCDs with the same controller chip that you have in your's and they've both work flawlessly.

[hanleychan]

I think I might just get a new one and start over from scratch. I think I ruined this lcd because there are now some dead pixels on the 3rd and 4th row

[hanleychan]

I don't think it matters wheter I use the potentiometers to adjust contrast or not because I don't think its a contrast problem I'm having. I've tried tieing pins 18-25 on the db25 connector and then soldering it to pin 1 and I still get the same result. I've just about given up

[The Coolest]

{BC}Helix:
I saw how your LCD screen looks, and I was wondering about the spectrum analyzer at the most bottom of the screen playing MP3s.
How did you manage that? I got that LC display plug in, and I can't get it to display it. What software did you use? or if you have this same plug in, please explain how you configured it to do this.

[hanleychan]

btw does anyone know where I can get another 4x20 lcd for cheap. I was looking at eio.com but the only 4x20 model that they have is sold out and the crystalfontz.com ones are way too expensive and their shipping cost to Canada is outrageously high. I would prefer a store located somewhere in Canada to keep shipping costs to a minimum if possible.

[The Coolest]

Ok, never mind. took me a while but I finally figured it out, on how to make this spectrum analyzer work.
Its a pretty cool effect.

[{BC}Helix]

Yeah it does look pretty cool. Oddly enough JALCDS and the winamp plugin that comes with it is the only thing that has ever succeeded in displaying an equalizer on my LCD. Everything else I've tried failed to put anything at all on the screen. In addition to getting a program that can display an equalizer when none other could, JALCDS is very open and full of choices of things to display on your screen, so it gets my vote for the best program out there. So i'm glad that you got it working TheCoolest. Hanleychan: I bought mine at crystalfontz.com like you mentioned above. I'm not sure where else you could get an LCD with that particular controller chip in Canada. you could try checking up on the classified on this site or on some other modding fourms to see if anybody is selling one near you or that would ship it to you for less.

[The Coolest]

you could also check ebay, here are some links:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26206&item=3810410944&rd=1&ssPageName=WDVW (Read the description, he sells those for $17 in his ebay store)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26206&item=3810568119&rd=1
a bit less than 9 hours left on the bid