topic Re: can not send string correctly to hyperterminal window. in S12 / MagniV Microcontrollers

can not send string correctly to hyperterminal window.

Gaoya — Sat, 17 Jul 2010 01:03:47 GMT

I am using EVM 8367 to learn how to program on freecale chip.

since I do not want to code with processor expert,I wrote code in C directly.

I set up a hyperterminal window on computer , bits rate 19200, 8 data bits, no parity , 1 stop bit. then I code as follows:

//***********************************************************************************************

#include <stdio.h>

#include <stdlib.h>

#define sci0br (volatile unsigned int *)0xf280

#define sci0ctr1 (vlatile unsigned int *)0xf281

#define sci0ctr2 (volatile unsigned int *)0xf282

#define sci0sr (volatile unsigned int *)0xf283

#define sci0dr (volatile unsigned int *)0xf284

#define tx 0x08

#define rx 0x04

/* prototype */

void init_sci();

void sci_outcstr(char *t);

void setsci0(char onoff);

#pragma interrupt saveall

void init_sci()

{

*sci0br=208;

*sci0ctr1=0x00;

*sci0ctr2=0x00;

}

void setsci0(char onoff)

{

*sci0ctr1=onoff;

}

void sci_outcstr( char *t)

{

unsigned short i;

while (*t!=0)

{

while (!(*sci0sr&0x8000)) { }

t++;

*sci0dr=*t;

for (i=0; i<30000; i++) { };

}

int main(void)

{

int i=0 ;

init_sci();

setsci0(tx|rx);

sci_outcstr("\nFreeScale\r");

for (i=0; i<30000; i++) {};

return(0);

}

//***********************************************************************

I always get some random characters in whole string like " F**rS*cal*".

Any idea? Thank you.

Re: can not send string correctly to hyperterminal window.

isionous — Tue, 27 Jul 2010 19:21:47 GMT

I couldn't find a good datasheet that discusses the SCI registers in detail, but if you link me to one, I might be able to help you further.

One of the first things to double-check your calculations to reach a SCI0BR value. Also, using a logic analyzer or oscilloscope to check the bit length of the SCI output of your microcontroller is very helpful.

Another thing I noticed is that your sci_outcstr function probably doesn't function like you intend it to. The way you handle the t variable means that you'll skip the first character of the string and output the null character. Assuming that you are using the sci0sr register correctly, you might want to change your sci_outcstr function to this:

void sci_outcstr(char *t){    while(*t)    {        while(!(sci0sr & 0x8000));        *sci0dr = *t;        t++;    }}

Note that the "t++;" and the "*sci0dr = *t;" are switched from your version.

Re: can not send string correctly to hyperterminal window.

isionous — Tue, 27 Jul 2010 20:01:16 GMT

...can't seem to edit my earlier post. Anyway, you should also make sure your main function never exits. I would advise replacing your for-loop in main with a "while(1);".