Re: [Sdcc-user] Setting up and sending serial messages

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

Hi Peter,

--- Peter <pl...@ac...> wrote:

> 
> Two solutions:
> 
> No interrupts:
> 
>  	// set TI at program start
>  	TI=1;
> 
>  	// write characters
>  	for(i = 32; i < 96; ++i) { // span ascii set
>  		while(!TI);         // wait until TI is 1
>  		TI=0;               // clear it
>  		SBUF=i;             // send a character;
>  	}


Ahh, ok, I had something similar to that before in my
code, but it didn't work.  Can't say it was exactly
what you have here, so I might have wrote it wrong.


> 
> With interrupts:
> 

Hmm, thats a tad bit more complicated with interrupts
;-)  


> Read the fine manual. You have to define putchar.
> SDCC has no idea what 
> is attached to the circuit, you have to write a
> function that does the 
> actual output. You could output to leds, a lcd, or
> serial. A synchronous 
> putchar suitable for serial from above would be:
> 
> // in init code, after SCON=... etc
> // you HAVE to set TI at the start of the program
> TI=1;
> 
> // send a character via serial line, suitable for
> printf() etc
> int putchar(int ch)
> {
>  	while(!TI); // wait until TI is set (it MUST be
> set in the init
>                      // code for the first character
> to go out!!!
>  	TI=0;       // clear
>  	SBUF=ch;    // send it out
>  	return((unsigned char)ch); // also return it as
> per standard C 
> }

Ahh, didn't know I needed to define my own putchar.  I
decided to try this first since I had the code already
set for using printf_tiny.  I added in the putchar
function and then tried to output some stuff to the
LCD screen.  However, only the first character of a
string is displayed and nothing else.  Not sure if its
because this putchar function is a synchronous one
(the lcd module wants asynchronous).  Any help would
be great.

Thanks!
J Silverman




		
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