problem with GPIO pin as input with nrf9160 using zephyr RTOS

[_bhanu]

Hi,

I'm using GPIO pin as input button  with nrf9160 using Zephyr RTOS, but when I was press the button I didn't get any response from button state.

hear is my code 

 

#include <zephyr/zephyr.h>
#include <zephyr/device.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/util.h>
#include <zephyr/sys/printk.h>
#include <inttypes.h>

#define SLEEP_TIME_MS	1000

#define button 6

void main(void)
{
	int ret;
	int count=0;
	
	 int gpio_dev =device_get_binding("GPIO_0");
       if(!gpio_dev)
       {
        printk("Cannot bind gpio device\n");
        return 0;
       }
	ret = gpio_pin_configure(gpio_dev,button, GPIO_INPUT);

	printk("Press the button\n");
	
		while (1)
		{
			int val = gpio_pin_get(gpio_dev,button);
			
			if (val!= 0)
			{
			count=0;
			}
			
			count++;
			printk("count =%d\n",count);
			k_msleep(SLEEP_TIME_MS);
		}

}

when I press button count  value not changing, if anyone know where I did wrong please help me to solve this.

thank you

[Depraz]

Hello,

device_get_binding returns a "const struct device" so  gpio_dev should be declared as 

const struct device *gpio_dev =device_get_binding("GPIO_0");

It is always good to look for returned value, so I would replace 

	ret = gpio_pin_configure(gpio_dev,button, GPIO_INPUT);

by

	ret = gpio_pin_configure(gpio_dev,button, GPIO_INPUT);
    if (ret != 0)
    {
        printk("Error %d", ret);
        return 1;
    }

Can you retry with those changes ? If this is still not working, make sure to have CONFIG_GPIO=y in your config and that the dts has

&gpio0 {
  status = "okay";
};

[_bhanu]

Hi Depraz,

I changed my code as you said ,after changing also I'm not getting any response form my button. if I changed pin config as

" ret = gpio_pin_configure( gpio_dev ,button, GPIO_PULL_UP); " then  its working fine in onboard  button. if I connect it to  external button  its not working. My external button is connected to nrf9160 as bellow figure.

.

is their any changes i have to do in my code if  I connect  button externally to board?

[Elfving]

Hello Bhanu,

As you are referring to external vs internal buttons, are you using the nRF9160DK?

When it comes the internal buttons, could you try GPIO_PULL_UP | GPIO_ACTIVE_LOW? If you take a look at the dts file of the 9160 you see these pin hardware characteristics defined.

You can also have a look at how this is done in the Zephyr button example, in which gpio_pin_configure_dt() is used instead of gpio_pin_configure().

When it comes to your external button, it looks like a pull-down switch. So could you try GPIO_PULL_DOWN for that one?

Regards,

Elfving

[_bhanu]

thanks you,

Elfving said:

When it comes the internal buttons, could you try GPIO_PULL_UP | GPIO_ACTIVE_LOW

now it's working for internal button.

Elfving said:

When it comes to your external button, it looks like a pull-down switch. So could you try GPIO_PULL_DOWN for that one?

when it come to external  button I tried "GPIO_PULL_DOWN" then also I'm not getting any response. Even if tried GPIO_PULL_UP then also not working.

[Elfving]

I see. Have you added the button to the dts files of your board? 

Regards,

Elfving

[_bhanu]

Hi Elfving,

thanks for reply.

Elfving said:

I see. Have you added the button to the dts files of your board?

can you help  me to fid the path to add button to dts file on my board.

[Elfving]

Sure! You would have to add this to the boards dts (device tree) file, either directly or by using an .overlay file. I believe it would be beneficial for you to read a bit about how these files work though, you can read about them and how they are used here in our new Dev Academy.

What GPIO have you connected the button to?

Regards,

Elfving

[_bhanu]

Hi,

Elfving said:

What GPIO have you connected the button to?

In my case i used gpio-15  is connected  to eternal button.

[Elfving]

Could you try creating an overlay file for your board with this addition? When you open the input files of your project in VSC you should see a shortcut for creating overlay files right there.

/ {
    buttons {		
        button4: button_4 {
            gpios = <&gpio0 15 (GPIO_PULL_DOWN | GPIO_ACTIVE_LOW)>;
            label = "Push button switch 4";
        };
    };
};

Regards,

Elfving