pwm

[ephraim]

Dear Sir.

A timer is defined for 1 hz,

Every 3 minutes or so we drive the buzzer with different pulses ( see code attached )

We are using the PWM to drive a buzzer ( 4khz ) ,

After 2 to 7 hours , the buzzer is not functioning. 

Once the pcb is reset , the buzzer start working.

k_timer_init(&my_timer, my_expiry_function, NULL); //Timer - 1 Hz
k_timer_start(&my_timer, K_MSEC(TIEMR_INTERVAL_SEC), K_SECONDS(TIEMR_INTERVAL_SEC)); //Timer - 1 Hz

// Buzzer timer.

k_timer_init(&bz_timer, bz_func, NULL);
k_timer_start(&bz_timer, K_SECONDS(1), K_MSEC(500));

static void work_buzzer_func(struct k_work * work_buzzer)
{
_BZ_SM.bz_state = bz_function(_BZ_SM.bz_state);
}

void my_expiry_function(struct k_timer *timer_id)
{
k_work_submit(&work_top);
}

}

uint8_t bz_function(uint8_t bz_state)
{
    static unsigned int led_time = 0;
    static unsigned int time = 0;
    static unsigned char a = 0;
    int times = 700000;

    switch(bz_state)
    {
    case 0 : //  BZ_silence.
        pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        a = 0;
        time = 0;
        break;
    case 1 :  // BZ_short_beep.
        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
             NRFX_DELAY_US(times);
             pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 2)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
            bz_state = BZ_silence;
        }

        time++;
        break;
    case 2 : // BZ_2_short_beep.
        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 1) // was 2 4  6
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 2)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 3)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
            bz_state = BZ_silence;
        }
        time++;
        break;
    case 3 :  // BZ_long_beep.
        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 10)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
            bz_state = BZ_silence;
        }
        time++;
        break;
    case 4 :  // BZ_siren.
        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }

        if(++time == 5)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
            bz_state = BZ_silence;
        }

        break;
    case 5 : // BZ_train.

        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 300, 150,0);  //  260, 130,
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }

        if(time == 2)
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);

        if(++time == 4)
        {
            time = 0;
        }
    case 6 : // BZ_charge.
        break;
    case 7 : // BZ_3_short_beep.
        if(time == 0)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 1)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 2)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 260, 130,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 3)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 4)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 240, 120,0);
              NRFX_DELAY_US(times);
              pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
        }
        if(time == 5)
        {
            pwm_pin_set_usec(pwm_dev,PWM_IO, 0, 0,0);
            bz_state = BZ_silence;
        }
        time++;

        break;
    }
    return bz_state;
}

How can I debug such behavior.

Please Advise.

[Kazi Afroza Sultana]

Hello Ephraim,

You can include some print statements into your code to debug so that it can be observed if the bz_function is called or not. Or other issue. 

Try this and let us know the output. 

Best Regards,

Kazi Afroza Sultana