wt is the difference bw PWM driver and PWM Library example

[saiteja]

(/attachment/182b723590b3c447267d5aed62b5405f)hi, i want to work on PWM to controll the vibration coin frequency for certain time period and also to change RGB values of LEDs so which example i can choose to understand PWM on nRF52.

#Edit:- /* Switch the polarity of the second channel. */ //pwm1_cfg.pin_polarity[1] = APP_PWM_POLARITY_ACTIVE_HIGH;

   /* Initialize and enable PWM. */
   err_code = app_pwm_init(&PWM,&pwm1_cfg,pwm_ready_callback);
   APP_ERROR_CHECK(err_code);
   app_pwm_enable(&PWM);

   uint32_t value;

      APP_ERROR_CHECK(err_code);
   while(true)
   {

       for (uint8_t i = 0; i < 40; ++i)
       {
           value = (i < 20) ? (i * 5) : (100 - (i - 20) * 5);
           //printf("value = %d\n",value);
           ready_flag = false;
           /* Set the duty cycle - keep trying until PWM is ready... */
           while (app_pwm_channel_duty_set(&PWM, 0, value) == NRF_ERROR_BUSY);

           /* ... or wait for callback. */
           while(!ready_flag);
           APP_ERROR_CHECK(app_pwm_channel_duty_set(&PWM, 1, value));
           nrf_delay_ms(50);

       }

   }

[Jørn]

Hello saiteja

The PWM driver and library provide two ways of generating a PWM signal on the nRF52. The PWM driver uses dedicated hardware to generate the signal, while the PWM library uses GPIOTE, PPI and timers in combination.

For more information on the two and their properties please see the following links to the infocenter

PWM driver (dedicated hardware):

infocenter.nordicsemi.com/index.jsp

PWM library (GPIOTE, PPI and timers):

infocenter.nordicsemi.com/.../lib_pwm.html

You can find links to descriptions of the examples you mentioned (pwm_driver and pwm_library in the examples->peripheral folder) on the pages of the infocenter links above.

Best regards

Jørn Frøysa

[Jørn]

The maximum output voltage from GPIO on the nRF52 series is VDD, so your maximum output voltage is dependent on the supply voltage. You need to make sure the output voltage from your low pass filter is within the specifications of your motor (2.7-3.3 V DC), considering your maximum PWM voltage is 2.8 V you may need to amplify the output of the filter.