LCD wont work :(

[mackrackit]

The 676 has ADC on port C. Might help to turn that off.
How do you have the LCD contrast pin connected?

[tiger_bel]

you are using 4bit datatransfer to display.
are the 4 bits connected to DB4 to DB7 on display side ???

rgds
tiger_bel

[EvilGhozt]

Wiring diagram:


This is how the LCD display looks like for about 1sek before the screen goes blank again..


Thanks for all help so far

[mackrackit]

Normally the contrast likes things on the "-" side. If you have a pot wire it like the example in the PBP manual. If not just try it going to the zero rail (-).

And PORTC 0-3 needs to be digital.

ANSEL = %00000000
That should turn all ADC off.
I think...

[EvilGhozt]

Normally the contrast likes things on the "-" side. If you have a pot wire it like the example in the PBP manual. If not just try it going to the zero rail (-).

And PORTC 0-3 needs to be digital.

ANSEL = %00000000
That should turn all ADC off.
I think...

If I set Vo (contrast) to GND, I wont even get the black squares at start.

ANSEL = %00000000 <- I try that, no change.

If I use a voltmeter on PortC 0-3 all are logic low (0volt) idle. In start before the LCD initailized portC 0-3 are logic high (5volt), is that right?

[aratti]

Your diagram in post #8 has the contrast pot wrongly wired. Correct the wiring as per the attached snap. Then adjust the pot till you have clean characters on LCD.

Al.

[EvilGhozt]

Your diagram in post #8 has the contrast pot wrongly wired. Correct the wiring as per the attached snap. Then adjust the pot till you have clean characters on LCD.

Al.

im not using any pot at all. I have just put the Vo to +5volt with resistor between, if thats wrong I wouldnt seen those black squares, right?