52832 PWM delay

[NORDIC_SUR]

I use timer+ppi+pwm model.my init code like this

void PWM_init()
{
/* ƵµÀµÄ PWM, 200Hz£¨5000us=5ms), ͨ¹ý ¿ª·¢°åLED ¹Ü½ÅÊä³ö. */
	app_pwm_config_t pwm0_cfg = APP_PWM_DEFAULT_CONFIG_1CH(250L, PWM_PIN);

	/* Çл»ÆµµÀµÄ¼«ÐÔ */
	pwm0_cfg.pin_polarity[0] = APP_PWM_POLARITY_ACTIVE_HIGH;

	/* ³õʼ»¯ºÍʹÄÜPWM. */
	err_code = app_pwm_init(&PWM0,&pwm0_cfg,pwm_ready_callback);
	APP_ERROR_CHECK(err_code);
	app_pwm_enable(&PWM0);//ʹÄÜPWM
	while (app_pwm_channel_duty_set(&PWM0, 0, 50) == NRF_ERROR_BUSY); 
}

I use some code to close and open PWM ,like this

void PWM_stop()
{
    app_pwm_disable(&PWM0);
}

void PWM_start()
{
    app_pwm_enable(&PWM0);
	while (app_pwm_channel_duty_set(&PWM0, 0, 50) == NRF_ERROR_BUSY);
}

question:I use oscilloscopes to check PWM, I find that when I start PWM,I must to wait about 260us before 52832 product PWM.

                 why I need to wait 260us?

[Jared]

Hi,

 Could you explain your measurement setup a bit more in detail?

• Are you measuring from the moment the CPU boots until the PWM signal is produced?
• Or are you measuring from the moment the function PWM_start() is called and until the PWM signal is produced?

If it's the latter, how are you signaling that the function PWM_start() is called?

Best regards

Jared 

[NORDIC_SUR]

Hi, Jared.

thank you for your answer.

I set pin17 to output high level after "while (app_pwm_channel_duty_set(&PWM0, 0, 50) == NRF_ERROR_BUSY);"

and then set pin17 output low level after I disable the PWM.

[Jared]

Hi,

I reproduced the measurement and measured 2.63 µs. Are you doing something else in your code besides using the pwm?

 Best regards

Jared

[NORDIC_SUR]

I use the PWM on the ble protocol stack.can you help me to try it on the ble protocol stack?

[NORDIC_SUR]

I find that I need to wait about 100us before  52832 stop pwm