Lcd Hd44780

[alaaodeh]

Hi All

i am use pic16f84a and hd44780 and i am connect the circuit and prgramed
this code
' PicBasic program to demonstrate operation of an LCD in 4-bit mode
'
' LCD should be connected as follows:
' LCD PIC
' DB4 PortA.0
' DB5 PortA.1
' DB6 PortA.2
' DB7 PortA.3
' RS PortA.4 (add 4.7K pullup resistor to 5 volts)
' E PortB.3
' RW Ground
' Vdd 5 volts
' Vss Ground
' Vo 20K potentiometer (or ground)
' DB0-3 No connect

Pause 500 ' Wait for LCD to startup

loop: Lcdout $fe, 1 ' Clear LCD screen
Lcdout "Hello" ' Display Hello
Pause 500 ' Wait .5 second

Lcdout $fe, 1 ' Clear LCD screen
Lcdout "World"
Pause 500 ' Wait .5 second

Goto loop ' Do it forever
and the output only draw blockes in first line
please heeeeeeeeeeeeeeelp meeeeeeeee

[BobK]

Hi alaaodeh,

First off, are you using PICBASIC compiler or PICBASIC PRO compiler? LCDOUT is not a valid statement in PICBASIC. Secondly, if you have the manual for the PICBASIC PRO compiler, there are samples for using this type of display with the 16F84A. Just looking at what you posted, where are the DEFINES that tell the PIC what you are doing with the LCD? Whatever you put after the ' are ignored by the compiler.

As for the blocks on the screen, this could be several things. The LCD controller might not be getting initialized properly or you may need to adjust the potentiometer for contrast.

There are numerous threads on this forum that deal with this exact subject matter. Take some time, use the SEARCH function, and look around a bit.

You aren't the first person to go through this learning process. But I can assure you that what you need to learn is on this forum already.

If you don't have the manuals, you can download them from the ME Labs website: www.melabs.com


BobK