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Unread 08-17-2003, 05:34 AM   #33
Turbokeu
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Join Date: May 2001
Location: Brussels - Belgium
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Quote:
Originally posted by airspirit
I think I found one at LCDMODKIT that only runs $65+16 ship out of Hong Kong. I'm going to prolly give that a shot ... it is green/black like the one at modwarehouse, and I'll just have to try to decipher the language at that site, hehe. I'm not about to spend three times that to order from modwarehouse, hehe.
This LCD should be OK. It needs the connection diagram for the Nan Ya LCD, with the following modifications:

1. The -12V side of the 10K contrast potmeter should go to pin 19 (Vee) of the LCD (the LCD has an integrated negative voltage charge pump for contrast control)
2. Following the datasheet the LCD must be reset at power on, so you need resistor R1 and capacitor C1 as in my schematic but connected to pin 9 (RST) of the LCD.
3. Font Selection signal FS is pin 18 on your LCD (not pin 19 as in the schematic) and should be connected to +5V.
4. On the Nan Ya schematic the data lines (DB0-DB7) are pins 11 to 18. On your LCD it is pins 10 to 17.
5. The datasheet is not very clear about the backlight specifications: it says it needs a forward voltage of 4.0 to 4.2V.
Since this LCD is a green/yellowish one, backlight LEDS are probably green or yellow LEDS (or a combination of the two).
Those above LED colors have a forward voltage each of 2.0 to 2.1V, so probably there are two leds in series to obtain the 4.0-4.2V forward voltage.
The problem is that we don't know HOW MUCH LEDs in total the BL is made of...so it's quite difficult to calculate the serial resistor for the BL.
Example:
Assuming there would be six leds in total (and 20mA per serial LED branch) : 3 parallel connections of 2 LEDs in series = 60mA.
The BL should be connected to the +5V through the following serial resistor (and taken into account the two limits given for the forward voltage:
(5-4.2)/0.06 = 13.33 Ohm (nearest E12 value is 12 Ohm)
(5-4.0)/0.06 = 16.66 Ohm (nearest E12 value is 15 Ohm)

I hope this sounds not too complicated...
Feel free to ask if you have more questions.

CD

Edit: Avoid green/yellow LCD's, they tend to be boring... (it's just my 0.05$)
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Last edited by Turbokeu; 08-17-2003 at 05:56 AM.
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