How to set GPIO pin to 0 volts

[saiteja]

Hi, i am working on PWM Library example in which i a m configuared GPIO pin P0.25. then i am getting voltage variations 1.3 to 2.8 volts.

the problem is when i disable the PWM and also by calling PWM_uninit. i am still getting some constant voltage that is 1.5 volts. i want to make this voltage to 0. how can it is possible.

Thankyou.

[Jørgen Holmefjord]

Have you configured the GPIO as output and set it to low? You can find the relevant functions in the GPIO abstraction documentation. If not configured, the pins will be left floating.

[Daniel Wang]

nrf_gpio_cfg_output(25); //config pin P0.25 as output

nrf_gpio_pin_clear(25); //set the pin low

[CBD]

As noted nrf_gpio_cfg_output(25) will set port0.25 as an output. nrf_gpio_pin_clear(25) will set port0.25 to 0 volts.

However, this is reliant on the port0.25 line not being driven high by other hardware on your board. Have you made sure that this isn't the case?

You could check this by setting the pin as an input and leave it free floating e.g. nrf_gpio_cfg_input(25, NRF_GPIO_PIN_NOPULL); , and then measure the voltage.

If a voltage is read that is somewhere in between ground and supply voltage then try grounding the line momentarily, to discharge any held charge, and then rechecking. A non-zero or near zero voltage will indicate that the line is being supplied form somewhere.