pwm always consume 300uA after app_pwm_init

[Sébastien Despont]

Hi,

I am using PWM for a buzzer. It is working, but the current consumption is always 300uA when PWM is not in use. This minimal current consumption appears right after the app_pwm_init function and never stops.

Could you confirm that this implementation is correct? Should I initialize the PWM instance for every use or can I resue an instance like in the code below?

APP_PWM_INSTANCE(PWM1,1);                   // Create the instance "PWM1" using TIMER1.

void pwm_ready_callback(uint32_t pwm_id)    // PWM callback function
{
}

void buzzer_kernel_init(void)
{
	uint32_t err_code;
	uint32_t duty = 50;

	// PWM
	app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_1CH(250, WATCH_BUZZER_PIN_D);
	err_code = app_pwm_init(&PWM1,&pwm1_cfg,pwm_ready_callback);
	APP_ERROR_CHECK(err_code);
	
	app_pwm_enable(&PWM1);		
	// Set the duty cycle - keep trying until PWM is ready...
	while (app_pwm_channel_duty_set(&PWM1, 0, duty) == NRF_ERROR_BUSY);			
	app_pwm_disable(&PWM1);

	// Do bip
	app_pwm_enable(&PWM1);		
	nrf_delay_ms(50);		
	app_pwm_disable(&PWM1);

	nrf_delay_ms(50);

	// Do bip
	app_pwm_enable(&PWM1);		
	nrf_delay_ms(50);		
	app_pwm_disable(&PWM1);	
}

void buzzer_kernel_on(void)
{
		app_pwm_enable(&PWM1);		
}


void buzzer_kernel_off(void)
{   
		app_pwm_disable(&PWM1);	
}

[Stefan Birnir Sverrisson]

Hi Sébastien

Yes, it seems like you need to call app_pwm_uninit(&PWM1) in order to free all allocated resources. After this call you will see low current consumption, but you will have to reinitialize the pwm again.

[Sébastien Despont]

Thanks for your feeback