Detecting a button double click?

[SteveKranz]

We are new to Nordic and have been making great progress with our nrf52840DK board and successfully running many of the Nordic SDK examples. We can't seem to find a single example of an API that will notify on a variety of button events (more than just a single click). Our code needs to respond differently for single-click, double-click, press-and-hold. Sure seems that the Nordic SDK would have something for that. Yes? Any help would be appreciated.

Thanks,

Steve K, PuzL Labs, LLC

[Priyanka]

Hi.

The same can be found for v2.4.1 as well: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.4.1/nrf/libraries/caf/caf_overview.html#:~:text=pressed%20or%20released.-,CAF%20click%20events,%EF%83%81,-Header%20file%3A 

Our applications like the nRF Desktop application, asset tracker etc use the CAF buttons library.

Regards,

Priyanka

[SteveKranz]

Hi Priyanka,

Thanks, good to know that v2.4.1 supports sensing button click events. I went looking within my v2.4.1 Nordic SDK installation to find a code example that might show the use of the "CAF: Buttons module". I couldn’t find anything. Being new to Nordic I guess it's possible I am looking in the wrong place. If you happen to have a tip I'd be grateful. Thanks in advance.

Regards,

Steve K, PuzL Labs, LLC

[Priyanka]

Please take a look at the nRF Desktop application where the CAF:Buttons module has been used.

-Priyanka

[SteveKranz]

Hi Priyanka,

Uggggg, I took a look at the recent link. Again, I'm coming up empty handed. Frankly, it doesn't seem that the question I'm asking should be this difficult to get to the bottom of. I wish that I could be directed to a very specific block of logic that demonstrates how a double-click of a button can be detected. (buttons like any of the four buttons on the nrf52840-DK board). I've given an honest look at the collection of CAF content in my SDK as well as the documentation and I find it lacking. It is by no means obvious how to answer my question from the general pointers I've been given in the direction of CAF. I am imagining that there really wouldn't be that much code involved, but if I don't know the various interfaces available and the syntax it's hard to get anything working. I typically am very good at hunting things down and reverse engineering. It was not so difficult for me to locate/generate the logic required for a single button click (non-CAF), I'll show it below. It would be fantastic if someone could just present an example with this level of detail that I could then leverage to get Button Double-Click Detection.

Button Single-Click Detection.

#include <zephyr/kernel.h>

#define Button_NODE DT_ALIAS(sw0)
static const struct gpio_dt_spec button = GPIO_DT_SPEC_GET(Button_NODE, gpios);
static struct gpio_callback button_cb;

static void button_callback(const struct device *gpiob, struct gpio_callback *cb, gpio_port_pins_t pins)
{
   // TBSL — do logic here to process single button press event.
}

static void Init_button()
{
    if (gpio_is_ready_dt(&button)) {
       gpio_pin_configure_dt(&button, GPIO_INPUT);
       gpio_pin_interrupt_configure_dt(&button, GPIO_INT_EDGE_TO_ACTIVE);
       gpio_init_callback(&button_cb, button_callback, BIT(button.pin));
       gpio_add_callback(button.port, &button_cb);
    }
}

int main(void)
{
   Init_button();
   while (true) {
      k_msleep(5000);
   }
   return 0;
}

[Priyanka]

Hi,

There does not seem an in-detail sample, but there is the CAF: Click detector module which can help. You can refer to the implementation details there, that does various click types, say, double click for instance. You can take a look at the click_detector code and copy the same method used here into your own application.

Regards.

Priyanka