jhd162a lcd related question

[electronicsIdiot]

hi,

I am trying for interfacing lcd with 89s52
for connection purpose I soldered the pins 1..16 with a connecto
so before interfacing I try to test it up.
**broken link removed**

When I connect 15(back LED+),16(back LED-) with battery yellow-green led light ups.

but When I connect 1(ground),2(Vcc),3(Vee contrast with a resistor ) with battery the rows or column of lcd shows no indication of life.
Is it shows my lcd got damaged or Is it ok to show nothing so that I can follow
to check LCD completely.

and also give me some easy and cheap methods by which I can check the lcd


....

 

[ckshivaram]

connect pin 3 with a variable resistor potentimeter and not fixed resistor.. connect pin 16 to ground via 330 ohm resistor....

adjust the contrast pot to see black box in lcd...

 

[electronicsIdiot]

connect pin 3 with a variable resistor potentimeter and not fixed resistor.. connect pin 16 to ground via 330 ohm resistor....

adjust the contrast pot to see black box in lcd...

ok do I make the connections in this way(connections at lcd with 10k trimpot vcc,vss,vee)
and also do i need two separate 5v(approx) supply?

**broken link removed**

 

[ckshivaram]

the lcd connection is correct..

you can tap or take the 5V regulator output supply going to controller and give it to lcd. use 12V/1A power supply. and connect pull up resistor to all the port pins of controller. then your lcd will work... lcd will not work properly if thre is not pull up resistors at everyport pin to which lcd pins are connected.

---------- Post added at 17:50 ---------- Previous post was at 17:48 ----------

pin 3 of lcd should be connected to middle pin of potentiometer. one end to 5V and other end to ground.

 

[d@nny]

the lcd connection is correct..

you can tap or take the 5V regulator output supply going to controller and give it to lcd. use 12V/1A power supply. and connect pull up resistor to all the port pins of controller. then your lcd will work... lcd will not work properly if thre is not pull up resistors at everyport pin to which lcd pins are connected.

I cant understand why pull up resistors for lcd as i think the pic16f84 outputs are Push–pull or totem pole? am i right? or i still need to use pull up resistors?

 

[ckshivaram]

better you use it always, to protect your port pins... Its a good practice to use it irrespective of controller...

 

[electronicsIdiot]

hi
sorry for late reply

I have a book "The 8051 uC and Embedded System" Mauhammad Ali Mazidi, Janice Gillispie Mazidi, Rolin D. McKinlay

in the book it says for port 0 pull up is required pull up resistor stating reason is it is Gate of Mos or base of TTL and port 3 is for interrupt purpose and external memory interfacing purpose so can I do the thing without pull-up resistor by leaving port 0.

thanks in advance.

 

[ckshivaram]

practically they say there are internal pull up resistor for 3 ports, but you cant rely on something internal... what if it is damaged, or non functional.. So it is better to use an external pull up resistor for all the ports if they are used for interfacing with any external device....

 

[electronicsIdiot]

hi,

thanks for your precious help

i uploaded a short video