nRF Gpio configuration

[Nishith]

Hi. i am trying to turn ON a LED1 and read its status and then turn ON LED2 based on status of LED1 in nrf52840dk board.

#define led1 28
#define led2 25
#define Button 12

int main(void)
{
NRF_LOG_INFO("========================================================");
NRF_LOG_INFO(" nRF52840 GPIO test");
NRF_LOG_INFO("========================================================\r\n");

nrf_gpio_cfg_input(Button,NRF_GPIO_PIN_PULLUP);

nrf_gpio_cfg_input(led1, NRF_GPIO_PIN_PULLDOWN);
nrf_gpio_pin_dir_set(led1, NRF_GPIO_PIN_DIR_OUTPUT);
nrf_gpio_pin_clear(led1);

nrf_gpio_pin_dir_set(led2, NRF_GPIO_PIN_DIR_OUTPUT);
nrf_gpio_pin_clear(led2);

while (true)
{
if(nrf_gpio_pin_read(Button)==0) //Read GPIO
{
nrf_gpio_pin_set(led1); //Turn ON the LED
}
else
{
nrf_gpio_pin_clear(led1); //Turn OFF the LED
}

if(nrf_gpio_pin_read(led1)==0) //Read GPIO
{
NRF_LOG_INFO("LED Off");
nrf_gpio_pin_clear(led2);
}
else
{
NRF_LOG_INFO("LED On");
nrf_gpio_pin_set(led2);
}
}
}

I have read that we to configure led as "input" to read the state and we have to configure it as "output" pin to change the state.
So I have configured it as input and output both. The code is working. But is this the correct way. 
I am using LED2 only to test whether i can read the LED1 pin. Please let me know whether this will cause any problem
I used the Blinky code provided by nrf SDK and made changes.
Thank you.

[Priyanka]

Hi Nishith,

It is generally not recommended to set a single pin as both output and input as it can cause unwanted confusion and also maybe unwanted behaviour later on.

You could maybe try to read the state of LED1 into a variable and then use this to control the LED2 state.

Regards,

Priyanka

[Nishith]

Hi Priyanka

Thanks for the reply. But what did you mean by unwanted behaviour. Will the Gpio stop working or will it only be a Gpio state reading issue?