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Need PIC16F84A Cool Project

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Maybe your problem lies in the V0 - Contrast pin of the LCD. Make sure to connect it to trimer (VDD and GND) and the LCD to the central tap of it.
 
I have already connected the pin 3 (V0) to the central pin of a variable resistor, the other pin of the variable to GND, and the other one to VCC and consequently to pin 2 of the LCD... Isn't that right :?:
 
Agent 009 said:
I have already connected the pin 3 (V0) to the central pin of a variable resistor, the other pin of the variable to GND, and the other one to VCC and consequently to pin 2 of the LCD... Isn't that right :?:
Yep, and when you turn it, the blocks apppear more or less visible, right?
 
Euh, actually, it appear Visible/Not visible... It's very sensitive... But the problem is: I just see a fully fulled screen...
 
Agent 009 said:
Euh, actually, it appear Visible/Not visible... It's very sensitive... But the problem is: I just see a fully fulled screen...
Is that LCD brand new or is it a used one? Onece I had a problem with used one, it was damaged and didn't work, and it took me a while to figure it out.
 
It's brand new!! I bought it 2 days ago :cry: :cry: !!
Jay, could u direct me 2 somewhere where i can actually learn how 2 'speak' with it... I don't want ready-made program: I like 2 create my own... But I need to quite understand how it works...
 
Agent 009 said:
By the way, I'm using Nigel's code (Gr8 site Nigel :wink: ), but it's for 628... Did u c it, Jay?
I wrote my own right from the scrach. Look for Hittachi HD44780 datasheet, it should have enaugh info to make your own program.
 
What's with the Hitachi? I'm using a WinStar... They have extremely 'tight' datasheets... Just the pin config and currents and stuff... No further info. I need to know what I do with each pin, not what is each pin...
 
Agent 009 said:
What's with the Hitachi? I'm using a WinStar... They have extremely 'tight' datasheets... Just the pin config and currents and stuff... No further info. I need to know what I do with each pin, not what is each pin...
That's why we use Hittachi datasheet instead. All 2*16 line LCDs (most of them) are Hittachi compatible.
 
Agent 009 said:
That's very refreshing :shock: ! Hehe, I want now the LCD to work!
But I have the 16F84A... Not the 16F628, which Nigel based his tutorials on... I took out the comparator line, from the code, and changed the porta/trisa to portb/trisb (cause it's 8-bits) and it didn't work :cry: :!: :!: :!:

The LCD code works fine on any 14 bit PIC, it's certainly fine on PortB of a 16F84, or any full port on a 16 series (14 bit) PIC. In fact, it will probably work on almost any PIC, with only very minor changes.

As already suggested, the contrast setting is fairly important, two low and you get nothing, too high and you often get solid black charcaters right across the screen. If ALL you get is solid blocks, it usually shows that the LCD isn't being set up - this is what you get if you don't have the PIC plugged in.
 
Nigel, I am trying another setup...
 

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I'm sure it's no resistor-contrast problem, because I am tuning a 'precise' 4k potentiometer... As soon as I get any liquid crystal appearing, I get'em as blocks... It's not that I have 2 much contrast or so...
 
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