Hello,
What should I do with unused GPIO pins on the nRF51822?
Imran
Hello,
What should I do with unused GPIO pins on the nRF51822?
Imran
Hi Imran,
The default behavior of unused GPIOs (it's reset value) is set as input, with an internal switch (NRF_GPIO->PIN_CNF[], bit 1) set to disconnect. This is the recommended configuration of unused GPIOs to ensure that they do not draw current due to floating inputs.
So, just keep the unused pins un-connected on your custom PCB and make sure that these pins have the reset value of NRF_GPIO->PIN_CNF[].
Cheers, Håkon
Hi Imran,
The default behavior of unused GPIOs (it's reset value) is set as input, with an internal switch (NRF_GPIO->PIN_CNF[], bit 1) set to disconnect. This is the recommended configuration of unused GPIOs to ensure that they do not draw current due to floating inputs.
So, just keep the unused pins un-connected on your custom PCB and make sure that these pins have the reset value of NRF_GPIO->PIN_CNF[].
Cheers, Håkon
So the pin is kept floating on the PCB but the internal switch is disconnected?
Yes, that is correct.
Hi Hakon,
i have set the internal switch of unsed pin to 1 ( disconnect). But if i measure the the voltage on the pin, for some of them is 3 V for the other 0. is it normal?
Thanks.
No worries. That is normal when configured in this GPIO-disconnect mode.