Does the NRF51x22 have 31 or 32 GPIOs?

[Nick Pelis]

Hello--

I have an NRF51422-DK devkit (PCA10028, v1.1.0) and noticed that pin P0.31 is not brought out to the connectors or mentioned anywhere in the nRF51-DK-HW schematic (download link). Also if you look at the specifications on Nordic's website, it very clearly states that there are 31 GPIOs here:

However, if I look at v3.0 of the nRF51 Series Reference Manual, it very clearly states in multiple places that there are 32 GPIOs (check section 14):

So what's the deal Nordic? Are there 31 or 32 GPIOs?

[RK]

The deal is you need to read the product sheet on the chips themselves where you will find that the QFN48 package has 31 GPIOs and the WLCSP packages have all 32.

There aren't enough pins available on the QFN48 package to have every GPIO routed out.