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PostPosted: Mon Feb 13, 2006 18:48 
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Joined: Thu Feb 09, 2006 23:14
Posts: 5
Hello!
I'm quite new with this, i havn't connected a lot of LCD displays in my life :)

But now i'm going to try to set up a 240*64 graphic display.
here is a picture:
Image

here is the datasheet: http://www.edtc.com/EDT/Products/Specs/339.pdf

Can I use this scheme?
Image

with this pinout instead:

1--- Ground
2--- Ground
3--- +5V
4--- -6 (how will i get this?)
5--- 16
6--- 14
7--- 1
8--- ?
9--- N/C
10--- +5V (the reset circuit)
11--- 2
12--- 3
13--- 4
14--- 5
15--- 6
16--- 7
17--- 8
18--- 9
19--- +5V
20--- N/C
(N/C = No Connection)

How can i get -6V?
where do I attatch the contrast pot?

Thanks in advance!

Edit: can i use this http://www.aaroncake.net/circuits/vinvertr.htm

or can i simply use the -7V from the molex? min -2V Max -10V is the specs!


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PostPosted: Mon Feb 13, 2006 21:52 
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Joined: Wed Aug 03, 2005 20:27
Posts: 130
Location: .fi
Can't open the datasheet currently so I cannot verify the connections, but for the negative voltage you can NOT use the molex trick. That only works for devices which do not have any other electrical connections (like the fans it's usually used for).

The solution on that page is not very handy (it's simple tho) as it needs more positive voltage than the created negative voltage is. There are links to circuits on this forum which can create enough negative voltage for LCD from a simple 5 volt source.


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PostPosted: Mon Feb 13, 2006 21:57 
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Joined: Thu Feb 09, 2006 23:14
Posts: 5
Hmm Zee dit you notice my edit?

"can i use this http://www.aaroncake.net/circuits/vinvertr.htm"

and, i have the datasheet on my computer, but i dont know where i can upload it now, will return with it soon!

edit: Here it is!: http://www.andersnyman.com/pic_page/upload/339.pdf


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PostPosted: Mon Feb 13, 2006 23:07 
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Joined: Wed Aug 03, 2005 20:27
Posts: 130
Location: .fi
Yes I saw it, that was the inverter I was talking about.

About the wiring:

LCD - LPT
1 - 18-25
2 - 18-25
3 - 5V
4 - Inverter
5 - 16
6 - 14
7 - 1
8 - 17
9 -
10 - Either build the reset-circuit or connect it to 5V
11 - 2
12 - 3
13 - 4
14 - 5
15 - 6
16 - 7
17 - 8
18 - 9
19 - Ground OR 5V
20 -

For the backlight connect 5V through a 10-15 ohm resistor and ground.


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PostPosted: Tue Feb 14, 2006 22:45 
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Joined: Thu Feb 09, 2006 23:14
Posts: 5
Thank you zee!
Why do i whant the reset-circuit?

Do you have a better idea for the negative voltage, i have a 5V mobilecharger i can use to hook up the backlight and VEE. Do you think i can use the charger for everything if i find another scheme for the negative voltage?

the specs on the charger:
input: 230V-AC/50Hz/12mA/4.6VA
output: 5V-DC/300mA/1.5VA


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PostPosted: Wed Feb 15, 2006 1:53 
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Joined: Wed Aug 03, 2005 20:27
Posts: 130
Location: .fi
The reset circuit is not mandatory. Only if it's absolutely necessary to give it a proper reset for it to work correctly after powerup.

The charger should work just fine for powering it (I'm using the handy extra molex connector behind my PC powersupply).

http://oms.wmhost.com/lcd/max.gif

This is the circuit I myself use for the negative voltage with my LCDs.


Last edited by Zee on Fri May 19, 2006 13:58, edited 1 time in total.

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PostPosted: Wed Feb 15, 2006 12:59 
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Joined: Thu Feb 09, 2006 23:14
Posts: 5
hmm, i dont know where to find the MAX749-chip in sweden :(
Sending a few e-mails to electronics suppliers in sweden.

tried the backlight:

off:
Image

on:
Image


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