How to configure external pin interrupt with nRF51822?

RE: How to configure external pin interrupt with nRF51822?

Håkon Alseth — Thu, 08 May 2014 07:18:30 GMT

The library uses the timer for the "detection delay". The actual pin-interrupt occurs in "void GPIOTE_IRQHandler(void)" (app_gpiote.c), as he app-button lib registers itself as a GPIOTE-user in the init function.

RE: How to configure external pin interrupt with nRF51822?

Jarmo — Thu, 08 May 2014 07:08:06 GMT

Thanks, I checked the code. For me, it looks like it is using a timer to poll the pin. The code is as below (clipped). There is no hint about using interrupt, except the timer, or do I misunderstand?

    // Configure pin.
    nrf_gpio_cfg_input(p_btn-&gt;pin_no, p_btn-&gt;pull_cfg);
    
    // Build GPIOTE user registration masks.
    m_active_high_states_mask |= ((p_btn-&gt;active_high ? 1 : 0) &lt;&lt; p_btn-&gt;pin_no);
    m_active_low_states_mask  |= ((p_btn-&gt;active_high ? 0 : 1) &lt;&lt; p_btn-&gt;pin_no);
}

// Register button module as a GPIOTE user.
err_code = app_gpiote_user_register(&amp;m_gpiote_user_id,
                                    m_active_high_states_mask,
                                    m_active_low_states_mask,
                                    gpiote_event_handler);
if (err_code != NRF_SUCCESS)
{
    return err_code;
}

// Create polling timer.
return app_timer_create(&amp;m_detection_delay_timer_id,
                        APP_TIMER_MODE_SINGLE_SHOT,
                        detection_delay_timeout_handler);

RE: How to configure external pin interrupt with nRF51822?

Håkon Alseth — Wed, 07 May 2014 13:25:40 GMT

Hi Jarmo,

Most ble-* prefixed examples in the nRF51822 SDK uses a module called "app_button" which you can use to generate a pin-interrupt. See function "buttons_init" in ble_app_hids_mouse for instance.

This library also includes a simple debounce (or detection delay as it's called in the lib)

Best regards Håkon