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how to test LCD

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danae_fiz

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how can i test a 16X2 LCD? do i just connect the Vss and Vdd to source to see if it's working or not? please help. if there's 2 pins with +Vled and -Vled how to connect it so that the back panel light for the LCD is on??
thanks
fiza
 

Nigel Goodwin

Super Moderator
Most Helpful Member
danae_fiz said:
how can i test a 16X2 LCD? do i just connect the Vss and Vdd to source to see if it's working or not? please help. if there's 2 pins with +Vled and -Vled how to connect it so that the back panel light for the LCD is on??
thanks
fiza
If you connect the power lines and a contrast control (or strap it to maximum contrast), you can adjust the contrast control to see some blocks on one line of the display. It doesn't prove a great deal, but it shows it's not totally dead.

For the back light, simply connect as you would an LED, using a series resistor.
 

danae_fiz

New Member
connection

this the pin configuration of the LCD that i bought. but my circuit uses different pin.i 'll attach the circuit. i already tried connecting the power and contrast control(20K variable resistor) but nothing happen. does it require a programming for LCD driver??

1-Vss
2-Vdd
3-Vo
4-RS
5-R/W
6-E
7-14:DB0-DB7
15-16:VLED+ and VLED-
(RS stock no. :184-8538)

is this connection correct??Vee =Vo, Vss=GND, Vdd=+5V
thanks
fiza
 

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Nigel Goodwin

Super Moderator
Most Helpful Member
Pretty well all these LCD text modules are standard, they use the same Hitachi chip set (or clones of them) and connect the same. The picture you posted looked to be connected completely wrong, nothing like the pin connections you gave.

Have a look at my LCD connections from my tutorials at http://www.winpicprog.co.uk/pic_tutorial_lcd_board.htm which shows how I connect them. The circuit as shown, with 5V applied to it, should light the top row of characters as solid blocks when you adjust the contrast.
 

danae_fiz

New Member
thanks

thanks nigel, i'll try to change the connection according to your tutorial and get back to inform whether it works or not.
regards
fiza
 

danae_fiz

New Member
it works

hi nigel. thank you very much. my lcd is okay now after i changed the connection according to your tutorial.
 
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