RE: PWM

Jared — Tue, 30 Apr 2019 07:08:55 GMT

Hi,

The period is set by changing the frequency while the pulse width is set by adjusting the duty cyle. Here is an example from the documentation of the PWM library that shows how to setup a PWM signal:

APP_PWM_INSTANCE(PWM1,1);                   // Create the instance "PWM1" using TIMER1.
void pwm_ready_callback(uint32_t pwm_id)    // PWM callback function
{
    
}
/*
    ...
 */
ret_code_t err_code;
/* 2-channel PWM, 200 Hz, output on DK LED pins. */
app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_2CH(5000L, BSP_LED_0, BSP_LED_1);
/* 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(&PWM1,&pwm1_cfg,pwm_ready_callback);
APP_ERROR_CHECK(err_code);
app_pwm_enable(&PWM1);
uint32_t value;
while(true)
{
    for (uint8_t i = 0; i < 40; ++i)
    {
        value = (i < 20) ? (i * 5) : (100 - (i - 20) * 5);
        
        /* Se the duty cycle - keep trying until PWM is ready. */
        while (app_pwm_channel_duty_set(&PWM1, 0, value) == NRF_ERROR_BUSY);
        while (app_pwm_channel_duty_set(&PWM1, 1, value) == NRF_ERROR_BUSY);
        nrf_delay_ms(25);
    }
}

best regards

Jared