Count between two inpulsion

[loulou]

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

[Alban · Accepted solution]

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.

[loulou]

Thank you for your answer Alban.

I understood well what you said  for restart the flags but if i  restart the flags is what my count will pass by again has 0 too ??

Now I go to test the restart flag.

Thank