Summary: in read_busy_flag you are switching the wrong TRIS

That you removed the call to LCD_set_position and it worked suggests
something that function does is wrong.

Looking at that function, I'm puzzled by the first two lines;

extern void LCD_set_position(unsigned char position) {
        unsigned int data;
        LCD_data =3D data;

It doesn't seem necessary to write the uninitialised variable to the
register.  But it is probably harmless.

Last thing in the function is to call read_busy_flag, a misnamed
function because it does more than read, it loops until DB7 is
true.

Now since all bits in TRISD are cleared, and never set, the read of
RD7 will fetch the output register bit only, which if it is LOW will
loop at that point forever, but if it is HIGH will return from
read_busy_flag prematurely, before the LCD has finished what you asked
it to do.

Perhaps you intended to modify TRISD instead of TRISA twice in
read_busy_flag?

On Fri, Oct 23, 2015 at 04:47:20AM -0500, Richard R. Pope wrote:
> David and et al,
>      Success, success!! I commented out the cursor position line and I=20
> just left the print character 'a' line. I have an a on the LCD. I really=
=20
> appreciate all of the help everybody.
> Thanks a bunch,
> rich!
>=20
> On 10/23/2015 4:02 AM, David Duffy (AVD) wrote:
> > Also add this line at the top of the main function:  ADCON1 =3D 0x0F;
> >
> > This will disable the analog inputs.  The data sheet says analog won't
> > override a pin set as output, but I'd add that line to make sure.
> > David...
> >
> > On 23/10/2015 6:48 PM, Richard R. Pope wrote:
> >> Alan,
> >>        I probably have but I can't find it. This PIC is a lot more
> >> complicated than a 16f84a. So I have turned to you folks for help and
> >> guidance. I have poured through the datasheets and the code over and
> >> over. I suspect that when we find it it will be one of those ah, how d=
id
> >> I ever miss that?
> >> Thanks,
> >> rich!
> >>
> >> On 10/23/2015 3:38 AM, alan.b.pearce@stfc.ac.uk wrote:
> >>> I haven't the time to look through your code, but I am wondering if y=
ou have messed up the RA port initialisation so that the rs pin is open col=
lector without a pullup.
> >>>
> >>>
> --=20
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--=20
James Cameron
http://quozl.linux.org.au/
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