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Interrupts using TIMER A interval

Brock
Intellectual 970 points
Other Parts Discussed in Thread: MSP430FW427, MSP430F2274

So I'm just experimenting with getting an interrupt to work correctly. My code is:

#include "msp430fw427.h"

#include "intrinsics.h"

 

#define LED1 BIT3

#define LED2 BIT4

 

void main (void)

{

  WDTCTL = WDTPW|WDTHOLD;

  P2OUT = ~LED1;

  P2DIR = LED1|LED2;

  TACCR0 = 49999;

  TACCTL0 = CCIE;

  TACTL = MC_1|ID_3|TASSEL_2|TACLR;

 

  __enable_interrupt();

 for (;;)

 {

 }

 

}

#pragma vector = TIMER1_A0_VECTOR

__interrupt void TA0_ISR(void)

{

   P2OUT ^= LED1|LED2;                      // set timer status flag

}

 

Instead of toggling the LEDs; the only thing that is happening is LED1 is staying on while the other stays off. Any ideas why they aren't toggling?


Thanks,

  • 0
    TI__Mastermind 24180 points

    If you set a breakpoint in the ISR does the PC reach it? If not then I suspect your interrupt vector definition may not agree with your timer setup. The following is from the FW427 header file:


    #define TIMER0_A1_VECTOR    (5 * 2u)  /* 0xFFEA Timer0_A CC1-2, TA0 */
    #define TIMER0_A0_VECTOR    (6 * 2u)  /* 0xFFEC Timer0_A CC0 */
    #define TIMER1_A1_VECTOR    (12 * 2u) /* 0xFFF8 Timer1_A CC1-4, TA1 */
    #define TIMER1_A0_VECTOR    (13 * 2u) /* 0xFFFA Timer1_A CC0 */

     /* Alternate Names */
    #define TIMERA1_VECTOR      TIMER0_A1_VECTOR
    #define TIMERA0_VECTOR      TIMER0_A0_VECTOR

    Try using "TIMER0_A0_VECTOR " instead of TIMER1_A0...

  • 0 in reply to Brandon08
    Guru 17650 points

    Hi Brock,

    only made some minor modifications to the app to make it usable for eZ430-RF2500 (LED connections, different MCU).

    Result: IT WORKS PERFECTLY!

    Question: What is your Main clock (in MHz)? Did you configure your clocks?

    Rgds
    aBUGSworstnightmare

     

    #include "msp430f2274.h"
    #include "intrinsics.h"

    /*-----------------------------------------------------------------------------
    // Compiler switches
    // used as:
    //            #ifdef  SOMETHING
    //                ...        ; additional code lines for test version only
    //            #endif
    // ONLY USE ONE AT AT TIME!!!!!!!!!!!!!!!!
    //---------------------------------------------------------------------------*/
    //#define SLOW                           // slow MCLK settings
    #define FAST                           // fast MCLK settings

    // defines for eZ430RF2500T
    // LED were connected to PORT1
    #define LED1 BIT0
    #define LED2 BIT1

    void main (void)
    {
      // disable watchdog timer
      //------------------------
      WDTCTL = WDTPW + WDTHOLD;               // Stop WDT

      // clock setting
      //------------------------
      #ifdef FAST
      DCOCTL = CALDCO_16MHZ;                   // Set DCO to 16MHz
      BCSCTL1 = CALBC1_16MHZ;                  // MCLC = SMCLK = DCOCLK = 16MHz
      #endif
     
      #ifdef SLOW
      DCOCTL = CALDCO_1MHZ;                   // Set DCO to 1MHz
      BCSCTL1 = CALBC1_1MHZ;                  // MCLC = SMCLK = DCOCLK = 1MHz
      #endif
      BCSCTL1 |= DIVA_0;                      // ACLK = ACLK/1
      BCSCTL3 = LFXT1S_2;                     // LFXT1 = ACLK = VLO = ~12kHz
      BCSCTL3 &= ~LFXT1OF;                    // clear LFXT1OF flag, 0
     
      P1OUT = ~LED1;
      P1DIR = LED1|LED2;
      TACCR0 = 49999;
      TACCTL0 = CCIE;
      TACTL = MC_1|ID_3|TASSEL_2|TACLR;
     
      __enable_interrupt();
      for (;;)
      {
          __no_operation();
      }
    }
    #pragma vector = TIMERA0_VECTOR
    __interrupt void TA0_ISR (void)
    {
      P1OUT ^= LED1|LED2;
    }

  • 0 in reply to Joerg Quinten
    Intellectual 970 points

    Thanks guys; this stuff is going over my head a bit so I'm gonna chill out a bit and read up on clock configurations/etc. Pretty sure that's why my interrupt isn't working. Just gotta work it out.

  • 0 in reply to Joerg Quinten
    Intellectual 645 points

    hi aBUGSworstnightmare, the code you posted works, but once i inserted the following code (using the definitions from the files slaa325a.zip):

        if (a>=2)
        {
          TI_CC_LED_PxOUT ^= TI_CC_LED2;
          a=0;
        }
        a++;     
        // __no_operation();     // commenting this in my code

    in the for(;;) loop, then the led defined by TI_CC_LED1 blinks ok using the timer interruption, but TI_CC_LED2 doesn't blink at all.

    what am i setting wrong?

    i am trying to fix another problem i have, and i think the solution for this will help me.

    beforehand, thanks a lot.

    regards,

    gustavo

     

  • 0 in reply to gchaconr
    Guru 227245 points

    If TI_CC_LED2 equals LED2 in the posted code, and TI_CC_LED_PxOUT equals P1OUT, then just inserting the above code will toggle the LED2 on every second loop, which is at app. MCLK/20. So the LED is blinking with ~25kHz per MHz MCLK. I'd say it is a bit too fast for the naked eye. Perhaps an ultra-high-speed camera might see something? (or a scope)

  • 0 in reply to Jens-Michael Gross
    Intellectual 645 points

    thanks for the answer, you are right, it's too fast for the naked eye. what i meant to write in the code was something higher than 2 for the 'if' condition.

    anyway, i have increased that condition to 25000 (and checking the periods of the clock) and just now it is possible observe the blinking.

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