HI, i would like to build a project that consist a gas sensor to interface with JHD162A LCD and PIC16F876A.............may i get any suggestion what type of simulator can i use to test out the circuit.....

IF JHD162A LCD just shown BLACK SQUARE in the display what are the possible problem...???

 

HI, i would like to build a project that consist a gas sensor to interface with JHD162A LCD and PIC16F876A.............may i get any suggestion what type of simulator can i use to test out the circuit.....

IF JHD162A LCD just shown BLACK SQUARE in the display what are the possible problem...???

If all of the character locations are black squares then you need to look at your contrast control signal to make sure that it is in the proper voltage range.

hgmjr

 

I using a trimmer to control the contrast.....actually is the 1st line shown the black square.... it cannot show my ADC output at the LCD screen......
thx for your reply...............

 

Your LCD control commands from the PIC are probably not correct.

You may have tried to output binary data instead of converting it to ASCII first.

 

As hgmjr said it could be your contrast adjustment but if that does not help then check your LCD initialisation sequence.
I think the JHD162A uses the 44780 controller chip in which case you can get the data sheet here.
http://fab.cba.mit.edu/classes/MIT/863.05/classes/11_14/44780.pdf

Follow the initialisation sequence on pages 45-46 to the letter making sure you have the required delays at the start of the sequence and between instructions as indicated.