illegal_BP abd frequency changes

jayc66 — Thu, 12 Mar 2009 02:48:27 GMT

I am using an S08DZ16CLC and have designed a program to measure the voltage across two potentiometers and output the data on the CAN bus.

The program seems to work until it enters the calibration function when a push button is pressed. Upon entering callibration mode an LED is turned on and then off upon exiting the function. As the program is being run using a 4MHz crystal, the LED should be on for a minimum of approx. 4 seconds, but it is significantly less than this.

More seriously, when in this callibration function, the debugger will often complain of a frequency change and an illegal_BP and halt the running of the program. My code is shown below, any help would be greatly appreciated!

//CALIBRATION RESULTS - GLOBAL VARIABLES
static unsigned int brk_cal_max = 0;
static unsigned int brk_cal_min = 255; //set to max range so all values less than initial
static unsigned int brk_cal_result = 0;

static unsigned int ac_cal_max = 0;
static unsigned int ac_cal_min = 255; //set to max range so all values less than initial
static unsigned int ac_cal_result = 0;

//FUNCTION TO PERFORM PEDAL CALIBRATION

unsigned int calibrate_pedals() {

    unsigned long int a,n,m,p;
    /*
    asm{
    NOP
    }
    */

    PTCD_PTCD5 = 0;      //light LED1

//for(p=0;p<0xFFFFFF;p++){
//for(m=0;m<0xFFFFFF;m++){
    for(n=0;n<0xFFFFFF;n++){      //loop in cal mode

        for(a=0;a<5;a++) {

            ADCSC1_ADCH=0x0D;   //select rv2

            ADCSC1_ADCO=0;        //trigger conversion
            while (!ADCSC1_COCO); //remain idle until conversion comple

            brk_cal_result = (unsigned int)ADCRL;

            if(brk_cal_result>brk_cal_max){
                brk_cal_max = brk_cal_result;
            }
            if(brk_cal_result<brk_cal_min){
                brk_cal_min = brk_cal_result;
            }
        }

        for(a=0;a<5;a++){

            ADCSC1_ADCH=0x0C;     //select rv1

            ADCSC1_ADCO=0;        //trigger conversion
            while (!ADCSC1_COCO); //remain idle until conversion complete

            ac_cal_result = (unsigned int)ADCRL;

            if(ac_cal_result>ac_cal_max){
                ac_cal_max = ac_cal_result;
            }
            if(ac_cal_result<ac_cal_min){
                ac_cal_min = ac_cal_result;
            }
        }
    }
//}
//}

    PTCD_PTCD5 = 1;   //turn off calibration LED

}

//FUNCTION TO SEND ACCELERATOR AND BRAKE POSITION OVER CAN
static void send_can_data(unsigned long accelpos, unsigned long breakpos) {

    int n;
    while (!CANCTL0_SYNCH);   //test if synched to CAN bus

    while(!CANTFLG_TXE0);    //test to see which buffers are empty

    CANTTBPR = 0x00;
    CANTIDR0 = 0xD0;     //set CAN id.
    CANTIDR1 = 0x00;

    CANTDSR0 = (unsigned char)accelpos;
    CANTDSR1 = (unsigned char)breakpos;


    CANTFLG = 0x01;               //clear the buffer, transmit


    //while(CANTFLG_TXE0);        //wait for flag to clear

    CANTFLG = 0x00;

    PTBD_PTBD3=0;               //CAN light on
    for(n=0;n<0xFFFF;n++);        //delay
    PTBD_PTBD3=1;                 //CAN light off
}

void main(void) {

    unsigned int accel_result =0;
    unsigned long accel_total = 0;
    unsigned long accel_average = 0;
    unsigned long accelpos =0;

    unsigned int break_result =0;
    unsigned long break_total = 0;
    unsigned long break_average = 0;
    unsigned long breakpos =0;

    int n;
    int a;
    int b;


//    MCGC2 = 0x62;                        /* Set MCGC2 register */
/* MCGC1: CLKS=0,RDIV=7,IREFS=0,IRCLKEN=0,IREFSTEN=0 */
// MCGC1 = 0x38;                        /* Set MCGC1 register */
/* MCGC3: LOLIE=0,PLLS=0,CME=0,VDIV=1 */
// MCGC3 = 0x01;                        /* Set MCGC3 register */
// while(MCGSC_IREFST) {                /* Wait until external reference is selected */
// }
// while(!MCGSC_LOCK) {                 /* Wait until FLL is locked */
// }
// while((MCGSC & 0x0C) != 0x00) {      /* Wait until FLL clock is selected as a bus clock reference */
// }


    MCGC2_RANGE = 1;            // High freq clock range selected
    MCGC2_EREFS = 1;            // External Ref Clock selected to be Internal Osc
    MCGC2_ERCLKEN = 1;            // Ext Ref Clk Enabled

    while(!MCGSC_OSCINIT);        //wait for oscillator to initialize

    MCGC1 = 0x00;                //Multi-purpose Clock Generator config register1

    while(MCGSC_CLKST == 3);    //wait until output of PLL is selected as clock

    //MCGC1=0x80; //external ref clk selected, divided by 1
    //MCGC2=0x33;



    EnableInterrupts; /* enable interrupts */

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

//Initialise CAN

    CANCTL1_CANE = 1;        /* for test: MSCAN enabled, clock = OSC_CLK, listen only disabled, wake-up filter disabled */
    CANCTL0_INITRQ = 1;    /* init mode */
    while(!CANCTL1_INITAK);            /* wait for ack of init mode */

     CANCTL1 = 0x80;                   /* enable module with osc clk as source */
    CANBTR0 = 0xC1;            /* SJW = 1, SJW = 1, 4Tq jmpwdt prescaler = 2 */
    CANBTR1 = 0xD8;            /* SAMP = 1, 3 samples/bit, TSEG2 = 5, TSEG1 = 8, 15 Tq per bit */

    CANIDAC = 0x10;      //Initialise for 8bit mask
    CANIDMR0 = 0x00;     //All accemptance masks to 0x00 (accept nothing)
    CANIDMR1 = 0x00;
    CANIDMR2 = 0x00;
    CANIDMR3 = 0x00;

    CANCTL0_INITRQ = 0;    /* leave init mode */
    while(CANCTL1_INITAK);            /* wait for ack of init mode exit */

    CANTBSEL = 0x01;    //select transmit buffer TX0
    CANRFLG = 0x40;
    CANRIER = 0;
    CANTARQ = 0;
    CANTIER = 0x00;            /* transmit buffer empty interrupts disabled for TX0*/

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

    /*initialise ADC*/

    ADCCFG=0x90; //configured for low power, 8 bit, long samples, bus clk src
    ADCSC2=0x00; //see log book for value breakdown
    ADCSC1=0x21; //AIEN disabled, input channel 1

    APCTL1=0x02; //AD1 pin I/O control disabled, all others general I/O
    APCTL2=0x10; //all other pins general I/O, except adp12

    ADCSC1_ADCH=0x0D; //ensure channel 13, rv2 as input
    ADCSC1_ADCH=0x0C;

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

    //PTCPE_PTCPE5 = 1;     //PB1 pull up enable

    PTCDD_PTCDD5 = 1;     //set LED1 as calibration output
    PTBDD_PTBDD3 = 1;     //set LED2 as CAN output
    PTBDD_PTBDD6 = 0;     //set PB1 as input
    PTCD_PTCD5 = 1;       //make sure LED1 is initially off
    PTBD_PTBD3 = 1;       //make sure LED2 is initially off

    //read the ADC

    for(; {   //infinite loop
        //Test button on port B pin 6 for calibration mode
        if (!PTBD_PTBD6) {
            calibrate_pedals();
        }

        for(n=0;n<3;n++){

            for(a=0;a<5;a++){

              ADCSC1_ADCH=0x0C;

              ADCSC1_ADCO=0;        //trigger conversion
              while (!ADCSC1_COCO); //remain idle until conversion complete

              break_result = (unsigned int)ADCRL;
              break_total = break_total + break_result;

           }

           for(a=0;a<5;a++) {    //loop so 10 adc values read CHANGED FOR TEST

              ADCSC1_ADCH=0x0D;

              ADCSC1_ADCO=0;        //trigger conversion
              while (!ADCSC1_COCO); //remain idle until conversion complete

              accel_result = (unsigned int)ADCRL;
              accel_total = accel_total + accel_result;

            }

        }


        accel_average = accel_total/10;
        accelpos =((accel_average*256)/(ac_cal_max - ac_cal_min));

        break_average = break_total/10;
        breakpos =((break_average*256)/(brk_cal_max - brk_cal_min));

        accel_total = 0;
        break_total = 0;

        //delay loop provide time for CAN to respond
        //to ADC
        for(n=0;n<0xFFFF;n++);

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

        //Send over CAN
        send_can_data(accelpos, breakpos);


        __RESET_WATCHDOG(); /* feeds the dog */

       /* loop forever */
    /* please make sure that you never leave main */
    }
}

Any help would be greatly appreciated!!

Thank you.

Re: illegal_BP abd frequency changes

bigmac — Thu, 12 Mar 2009 07:36:38 GMT

Hello,

I suspect that your problem may be due to the need to repeatedly clear the COP timer during your wait loop. So COP reset would probably occur.

Regards,

Mac

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