Use Reset pin as a normal GPIO - nRF52832

[bhargav_gondaliya]

Hi, I am using a custom nrf52832 device. In that device , button is connected with reset pin P0.21. due to reset functionality I am not able get interrupt from button.

how can I use P0.21 as normal gpio??
Can I implement long-press functionality on P0.21 pin??

below is schematic of button and reset pin.

I have tried below possibilities
- used longpress node.

- disabled uicr node from dts.

- Remove GPIO as nRESET properties.

according to the documentation of nRESET.

while in nrf5 sdk it is working as gpio. why not in nrf connect sdk??

[X4ce]

Hi,

This might be helpful for you.

https://devzone.nordicsemi.com/f/nordic-q-a/100486/reset-pin-as-gpio/429399

Regards

[bhargav_gondaliya]

Thanks X4ce , how can I implement that solution in my application?
currently my setting.json looks like as below.

{
    "nrf-connect.taskBindings": {
        "pristineBuild": [
            {
                "taskName": "Build: long_press_v2/build (active)",
                "buildConfigs": [
                    "${workspaceFolder}/build"
                ]
            }
        ]
    }
}

[Simonr]

Hi

What version of the nRF Connect SDK are you using? In the latest versions (at least from NCS 2.7.0 and newer) the correct way to set the reset pin as a GPIO is through the devicetree. By default, the board's devicetree sets the GPIO as a reset with the following. Removing this line from the .dts file should make the reset pin function as a GPIO. This is documented in the Zephyr 3.5 migration guide: https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/releases/migration-guide-3.5.html 

&uicr {

    gpio-as-nreset;

};

Best regards,

Simon

[bhargav_gondaliya]

Hi Simonr 

I am using a nRF Connect SDK v2.6.0. I have tried that solution did not worked.

currently I have deleted gpio-as-nreset; property like as below.

&uicr {
    /delete-property/gpio-as-nreset;
};

is it validate according to the format?

also I added a line in setting.json file.

In vscode file/preferences/setting/"nrf-connect.flash.softreset": true (enabled from setting)

after that I able to use reset pin as gpio. but it is correct solution to use reset pin as gpio?? after that I am not able to connect a device via ble, not updating display etc..

because I want to implement single press and long press functionality on that pin.
below is my code for long press and single press

case if(pins & BIT(button_0.pin)){
        printk("button 0 pressed");
        LOG_INF("reset pressed\n\r");
        read_time(rtc_dev,(time_t *)&unix_time);
        uint32_t reset_pressed_epoch_time = unix_time;
        while (!gpio_pin_get_dt(&button_0) && (unix_time - reset_pressed_epoch_time) <= 10)
        {
            k_msleep(100);
            read_time(rtc_dev,(time_t *)&unix_time);
        }
        if (unix_time - reset_pressed_epoch_time > 10)
        {
            Reset_Flag=1;
            eeprom_write(i2c_dev,EEPROM_RESET_FLAG_ADDRESS, &Reset_Flag, 1);
            eeprom_write(i2c_dev,EEPROM_RESET_TIME_FLAG, &current_epoch_time, 4);
            guide_flag=1;
            eeprom_write(i2c_dev,EEPROM_DEVICE_GUIDE_ADDRESS,&guide_flag,1);
            reset_hardware_locally();
            //reset_hardware();
            k_msleep(1000);
            NVIC_SystemReset();
        }
        else
        {
            k_msleep(1000);
            NVIC_SystemReset();
        }
        break;

[Simonr]

Hi

Yes, it should be fine setting it up like this. You need to use the /delete-property/ if the gpio-as-nreset is set by default I believe. But why are you enabling the Softreset when flashing after doing so? The pin shouldn't be needed to do a full reset when flashing? Have you tried power cycling the board and see if it works afterwards when you've flashed it like this? A full power cycle might be needed after flashing the device when using softreset. 

What exactly are you using the reset pin GPIO for in your project?

Best regards,

Simon