Pic16f877a and interface to keypad and LCD in microbasic i want help

[lina889]

hello everybody
am trying to connect LCD and keypad to PIC16f877a but after compile the code
and connect the schematic in Proteus when i Press on the keypad no out put on the LCD
i upload the micobasic program and the Proteus here

 

[comtrek]

I can help you with this in assembly, if you may wish to opt for this.

 

[Californiajoe]

You forgot to connect resistors from keypad lines to GND.

Regards

 

[ayazahmed]

Californiajoe has given a good idea, but still its not working.

I think there is some mistake in ur code. I have downloaded the attachment, but it doesnot contain the (.PBP) file we have to check. It contains another file. PLZ attach the correct one so that i may be able to help u.

Regardz

Ayaz Ahmed

 

[comtrek]

The way you have connected the keypad, it requires in the logic that you make one set of pins input ie A,B,C,D or 1,2,3,4 the other as output, make all out put low, make the output of the key in row/col as high then sense it with the corresponding input or row/col for high voltage. Do this for all rows/cols in a loop. Please check this it should work.