Unexpected GPIO default state

[Jonathan]

(I'm developing a firmware on nRF52832, but had actually stareted on nRF51822 and observed the same issue, SDK 12, pending migration to SDK 15)

When my app starts, I output NRF_GPIO->DIR, and get a value of 4D5CE81... While I would expect all ports to be by default inputs, so 0x00000000...

This is the first thing I do in my main(). I also tried running without the softdevice, same result (and similar result on nRF51).

Now, I also try setting them all to my default:

for (unsigned char i = 0; i < 32; ++i)
{
  if (NRF_GPIO->PIN_CNF[i] == 0x02)
  {
    NRF_GPIO->PIN_CNF[i] = 0x06; // Input pulldown with disconnected buffer
  }
}

But not long after running this code, things will hang, breaking execution, it's somewhere inside the softdevice and it loops.

So my main question is: am I just getting everything wrong?

2.5.0.0

[Hung Bui]

Hi Jonathan, 

I suspect you were using wrong device definition and/or start up code. Could you let us know which IDE you are using ? And maybe post your code/project here ? 

We suggest to use Keil or Segger Embedded Studio. 

Could you try and test a nRF5 SDK ? The current SDK is SDK v15 (SDK v11 if you are using nRF51). 

If you want to test with bare metal code, you can have a look here.

[Jonathan]

Hi Hung,

Thanks for your reply, I'm currently using Keil. I unfortunately cannot share the code. So if I get it correctly, your suggestion is to try one of the SDK samples? I will do that next week and will let you know how I go (holidays at the moment). Thanks!

2.5.0.0

[Jonathan]

Sorry, tested on SDK15, works as expected!

2.5.0.0