Robert,

 Did you set the oscillator for HS operation as opposed to XT when
 you went to 20Mhz?  If not, the oscillator probably isn't starting
 or running at 20Mhz.  Just a thought.

                                          Regards,

                                            Jim



On Tue, 13 February 2001, Robert Shady wrote:

>
> I'm not sure if I should really latch on to this
> thread or not with my own problems, but they might
> be related to what your seeing as well, so I'll
> post what's happened to me so far...  Which is
> REALLY bizarre..
>
> *** WARNING -- THIS IS LONG! ***
>
> I've taken Mike's 2wirelcd circuit and wired it
> up, downloaded his 2wirelcd.asm code, compiled,
> and ran -- It worked fine @ 4mhz as stated.
>
> I need to be able to run it @ 20mhz, so I visited
> the time delay code generator at:
> http://www.piclist.com/cgi-bin/delay.exe
> and generated a replacement 160usec delay and
> 5msec delay and put it in a file called delay20.inc
> (thinking I can also make one called delay4.inc and
> just change 1 line of the code to switch between
> 4mhz & 20mhz).  I switched everything to use the new
> code and ran it @ 20mhz -- didn't work, tried it @
> 4mhz -- didn't work.
>
> I revisited the delay code generator and generated
> new 4mhz based delays for 160usec & 5msec and put
> them in delay4.inc, compiled and ran @ 4mhz -- nothing.
>
> Now here's the really funky part... I took the routines
> out of delay4.inc and put them in the lcd.asm code
> compiled and ran @ 4mhz -- worked perfectly.
>
> So I took the routines out of delay20.inc and put them
> in the lcd.asm code, compile & ran @ 20mhz -- nothing!
>
> Any clue?  Why would the routines work when compiled
> directly into the code, but not included?  Also, I
> couldn't even get the circuit to work just by
> interfacing directly with the PIC, I had to use Mike's
> little flip-flop circuit for some reason... Timing
> issues maybe?
>
> Does anybody have 16F84 (actually 16F84A) code for
> driving an LCD (preferrably with Mike's circuit, it's
> nice only using 2 pins) running @ 20mhz?
>
> -- Rob
>
> > --- David VanHorn <dvanhorn@CEDAR.NET> wrote:
> > > At 01:45 PM 2/13/01 +1100, Ian Hynes wrote:
> > > >PICers,
> > > >
> > > >Sorry to be a pain but I'm totally stymied with this. It's a 16F84
> > > >interfaced via 3 wires to an HD44780 LCD. I'm still learning this
> > > >stuff so
> > >
> > > You know the 44780 needs three wires, plus four for data, right?
> > >
> > >
> > >
> > > --
> > > Dave's Engineering Page: http://www.dvanhorn.org
> > > Where's dave? http://www.findu.com/cgi-bin/find.cgi?kc6ete-9
> > >
> > > --
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> > subtopics
> > > (like ads or off topics) for you. See
> > http://www.piclist.com/#topics
> > >
> > >
> >
> >
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>
>
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jim@jpes.com

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