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[Lcdproc] HD44780-winamp gets overflooded with Hearts after upgrading to CVS


Chronological Thread 
  • From: dura-zell AT dynamik.sytes.net (Sven Mertens)
  • Subject: [Lcdproc] HD44780-winamp gets overflooded with Hearts after upgrading to CVS
  • Date: Fri Mar 18 19:50:02 2005

Hi there!

As you told me, I replaced the '40' with '80' and compiled. The daemon
started up with the screwed up display. As I tested a program from an
other lcd-project before, this time there were half-blocks. I mean a
char where the upper half is blank and the lower half is "on".

To be sure this is not an effect of the change I made, I killed the
0.5.cvs and started up the 0.4.5. After starting 0.5.cvs there were the
hearts again.

After that I tried different values for uPause. I started with '10' and
finnished with 1000. After each change I did a "make clean", "configure"
and "make". But, as far as I could see the only thing that changed was
the value in hd44780.c, at the display changed nothing.

After I spent nearly the whole last weekend working through the code, at
Tuesday wanted to give up this nifty lcd. I didn't because I think there
may be a solution to my problem... At the weekend I've made some
experiments with delays too, but none worked.

So, thats what I can tell you.

Greetings, Sven


Andrés Trapanotto schrieb:
> [I've removed everything from previous mails. Please refer to the
> archive about them]
> Well, I'll try to start answering again; from the scratch.
>
> I'll suppose that when you turns on the LCD the LCD ram memory is
> filled with 0x00 values. Then, the char generator shows the screen
> clean; because it is representing the zero character that is clean too.
>
> When you start lcdproc, it fills the lcd text buffer with 0x20
> (spaces) *** and set the special caracter zero as the heart. It results
> in a clean lcd screen.
>
> *** Think about this: if there is some problem filling the lcd text
> buffer, it still be filled with 0x00 values and the screen will be
> fullfilled with hearts...
> I'm thinking that it is the problem, because the lcdproc framebuffer
> is filled with 0x20 spaces (you send a mail showing that).
> One common issue that can cause that is the delay time that the
> program have to wait to drive the parallel port signals. To do it,
> lcdproc uses a function called timing_uPause (you can find it in
> server/drivers/timing.h) and it can be compiled in three diferent ways.
> It can try to use one of these or you can force lcdproc the election
> process :)
>
> I can continue analizing it in this way, but you can try something
> quicker: try to add some delay in HD44780_flush() function (in
> server/drivers/hd44780.c) changing
> p->hd44780_functions->uPause (p, 40); // Minimun exec time for all
> commands
> to
> p->hd44780_functions->uPause (p, 80);
>
> You can try with something greater that "80" to...
> Well ... tell us your results :)
>


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