[Sdcc-user] Setting up and sending serial messages

[J S <g1p...@ya...>]

Hi All,

I know this is prolly a very simple question for all
you experts out there, but how do you setup serial
communictaions with sdcc when using an AT89C2051
controller?  I tried playing with some examples I
have, but they are all for Keil and don't seem to be
working.  

My basic goal is to send a "test" message to a serial
LCD display that requires 9600 baud rate and a 8 bit
data and 1 bit stop transmission with no parity.  I
wrote this up to initialize the serial communication:

SCON=0x50;
TMOD=0x20;
TH1=0xFD;
TR1=1;
T1=1;

This combination seems to be ok, as I can send one
letter to the display by:

SBUF='T';

But, if I send another letter that way, it just erases
the previous one.  I thought this might have something
to do with the display so I then sent a specific
command for it to shift the cursor over by one, but it
still didn't help.

Also, I did try to use printf_tiny but every time I
use it, I get a link warning:

?ASlink-Warning-Undefined Global '_putchar' referenced
by module 'printf_tiny'

And if I tried programming the 2051 even with that
warning, it won't work.

Not sure what I'm doing wrong, so any help would be
appreciated :-)

Thanks,
J Silverman


		
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