Count between two inpulsion

loulou — Thu, 20 Apr 2006 15:20:56 GMT

Hello Friend,

I work on the MC9S12XDP512EVB and I work whith code warrior 4.1.

Now I want to count a time between two inpulsions but a i have 2 or 3 small problem or/and questions.

First Question

is It possible not to use an interruption to manage the flags? Or rather the microcontrollor can make it of him same ?

Me i don't use the interruption.

My Program:

#define TCTL_3 (*((char*)0x004A))
#define TCTL_4 (*((char*)0x004B))
#define LECTURE (*((short int*)0x0050))
#define TEMPS (*((short int*)0x3000))

////////////////////////////////////////////////////////////////////////////////////////////

void main(void) {

init_timer();

for(; {

if ( TFLG1_C0F ) {
   TEMPS=LECTURE;
      }

}

////////////////////////////////////////////////////////////////////////////////////////////

static void init_timer(void) {

  TEMPS=0x0034;
  TIOS = 0xFE;
   TIE =0x00;
  TSCR2 =0x06;
   TCTL_3=0x00;
  TCTL_4=0x01;
  TSCR1=0xE8;

}

//////////////////////////////////////////////////////////////////////////////////////////////

My program makes first of all an initialization of the module timer and after i wait an inpulsion on IOS0.

But the problem the microcontrollor don't put the flags at 0 and me i can't it too.

this fact my count don't restart and i don't take a good count between two inpulsion.

Now I turn to you for your assitance. I looking for of information and assistance on this programmme so that it realise the operation which I wish.

But if you have a other similar program of this you can take me please.

thank you for your assistance

PS: I'm sorry for my bad english

Re: Count between two inpulsion

Alban — Thu, 20 Apr 2006 15:28:46 GMT

Salut Loulou !

Reading a value is not enough to clear a flag.

The general rule of thumb on S12 to clear a flag is:

- Read the register which has the flag set,

- Write a ONE to the bit you want to reset or to its associated ACK bit.

So, and I haven't looked at your example in particular, but:

You can check the flag sometimes (what you do with your IF) it is reading the register. But then, within the "if" you whould do something like

TFLG1_TOF = 1; or use an ACKnowledgment bit if exists.

Do you see what I mean ?

Alban.