I2S - sound problem

[KaEd1705]

Hi, 

I use the app_buton module to handle the buttons. When detecting a button interrupt I call a function that sends data to I2S (using the "app_sched_event_put" function):

static void button_event_handler(uint8_t pin_no, uint8_t button_action)
{
    switch (pin_no)
    {
        case 28:
        {
            NRF_LOG_INFO("Send button state change.");
            app_sched_event_put(NULL, 0, Sound_Play);
            break;
        }
        default:
            APP_ERROR_HANDLER(pin_no);
            break;
    }
}

When a button interruption is detected (pressing and releasing the button), a small click is heard in the speaker. What could be the reason? how can i solve this problem?

[Kenneth]

Hi,

Does the click also occur if you use app_sched_event_put(NULL, 0, Sound_Play); from an app_timer instead of an app_button callback?

Just trying to figure out of the noise is due to buffering issue the application, or analog noise from the button, what pull up resistor is used on the button?

Best regards,
Kenneth

[KaEd1705]

No, the click doesn't occur if I use app_sched_event_put(NULL, 0, Sound_Play); from an app_timer.

I used 4k7 resistor as pull up.

Regards,

KaEd1705

[KaEd1705]

I checked on the oscilloscope and there is a temporary interruption in i2s communication

[Kenneth]

It may sound like an interrupt priority/blocking problem, how about using pin change interrupt example instead as basis for your application?

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/pin_change_int_example.html

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/hardware_driver_gpiote.html

[KaEd1705]

Thank you, I think it helped, I will continue to test.

I have a similar problem when active bluetooth advertising (it is less audible). Could it be a hardware or firmware problem?