LCD Control

[mister_e]

by searching here and there this one is suppose to be PBP compatible without too much problem. At least the controller is suppose to be HD44780 compliant.

Did you tried a longer start-up delay, let's say 2 Seconds at the top of the program?
Do you have another LCD to test with your current set-up?
What about the supply line? Clean and 5V?
what about your current setup? Any schematic or picture of it?

Maybe a simple hardware problem. unsufficient filtering or else.

[alec]

hi boboco

Try adding a 10ms pause between the two LCDOUT statements. It's the only way I've been able to display multiple lines.

[boboco]

Hi Steve, Hi Alec,

Alec, I've tried all sorts of delays, or even different program parts, to write line 2, all without success, but thanks anyway.

Steve, I usually allow 1 sec. startup, but trying 2 secs made no difference. The setup is a control circuit for medical laser x-y-z control containing analog and digital circuits. This model is supplied via laboratory power supply, is smoothed and filtered (100nF everywhere) and the line shows ca. 20 mV ripple in operation. The oscillator is decoupled from the VCC line because that causes lots of nasty noise usually. If you wish, I’ll send you the circuit diagram.

The code is the usual:


DEFINE LCD_etc…. ‘Setup LCD

Pause 1000 ‘Settle pause

LCDOUT, $FE, 1, “ Blah blah” ‘Write #1

GOSUB somewhere ‘Fetch, calculate variable

LCDOUT $FE, $C0, “ Blah “, DEC Variable ‘Display variable

I haven't got another unit of this size and type, to take another type for test will involve (sigh) a large amount of work as this is built-in and direct connected. If I don't get it to work, though, I'll buy a new one eventually. I don't like getting beat, though.

One point, I’m using a 16F877 and have the LCD defined to the D-Port as the only port free. I’m wondering if some register needs to be set/reset. I’ve been caught like that before. Is anything known? I’ve not found anything in the PIC Data book, but something with the parallel port control possible?

Greetings,

Rob

[Rhatidbwoy]

I was having a problem with HANTRONIX 20 x4.

I fixed the problem with a pause. In description to what I was getting was that I would get the second line to go and the fourth line to go. Not the first nor the third line to light. I played with many things, but what came to work was that I need a pause.

When you write your first line you normally would not need a clear screen (lcdout $fe, 1). So the second thing would write. leaving nothing for hte first line. This is were the pause is needed. So it looks something like this:

lcdout $fe,1
pause 10 'what ever value. I used 10
lcdout $fe, address (first line), (what ever you want to write here)
lcdout $fe, address (second line), (what ever you want to write here)

This might lead to something good and it might not, but it is something worth your while to try. I tried this with the 20x4 HANTRONIX and I got my screen to do what I wanted it to do.

[boboco]

Hi Rhatidbwoy,

I've tried all sorts of delay times beween lines, nothing works. I've ordered a new display, as I suppose this one to be defect. Thanks anyway.

Greetings

[Acetronics2]

Hi, Boboco

Was it a 50% Discount ???

...

Seriously, you should ask a question about that on the Displaytech site ...

Alain

[Dave]

boboco, As Rhatidbwoy mentioned I have found in the past (8+ years) that most LCD displays require anywhere from 5 to 15 Milliseconds to execute a clear command "$FE,01" or a home command "$FE,02". I have found this to be true with displays from OPTREX,ITRON,and CRYSTALFONTZ. They are all compatable with HD44780 type lcd controllers found on most lcds. Also whenever I use a command to place the cursor to a different location on the lcd I always use "PAUSEUS 100" as I have found in the past some displays require this delay. I have had no problems with any LCD or VFD displays using delays in my software as I have mentioned. LOL

Dave Purola,
N8NTA