Kalle Pihlajasaari wrote:
>
> Hi Tony,
>
> >  I am having trouble initializing my 2x8 optrex lcd w/hd44780a
> > controller
> > in 4 bit mode.I have tried everything I could glean from the FAQ's but
> > it just
> > does'nt shift to 4 bit mode and all subsequent writes cause the cursor
> > to move
> > two places.In the simulator the write routine 4 bit writes upper
> > nybble,lower
> > nybble with no extra loops and the character printed bears no relation
> > to the
> > one I was attempting.I am using bits <4..7>b for data & bits <1..3>b for
> > control
> > The rs & r/w bits are output with enable low then enable is toggled high
> > and the
> > 4 data bits are output then the enable bit is toggled low.
>
> You might have a look at the following I did in Pascal just
> to get an idea of the steps to take.  The plan is to write
> the reset to 8 bit mode comand to the display 3 times as
> recommended in the data sheets and then send the set to
> 4 bit mode command once.  All 4 of the above were single byte writes
> after the last one then you start to write nibble/nibble.
>
Thanks I'll go and look.I did write my code just as you say like the
FAQ's I read
indicated I should. Plus a few variations.Is it necessary to pull the
unused inputs
to the lcd low externally ?
> http://www.ip.co.za/people/kalle/project.htm#lcd
>
> Cheers     *<<<-|
> --
> Kalle Pihlajasaari   kalle@ip.co.za   http://www.ip.co.za/ip
> Interface Products   P O Box 15775, DOORNFONTEIN, 2028, South Africa
> + 27 (11) 402-7750   Fax: 402-7751    http://www.ip.co.za/people/kalle