Softdevice hanging at startup

[Hugo Habicht]

Hi all,

I am having a problem with the startup of the software on an nRF52840. It works fine on an EVM but not on our own board. The software is hanging in the softdevice s140 before even reaching main() (on some boards only). I can see in the debugger when I stop the software that it is in address 0x2ff8 waiting for an external interrupt.  What is is waiting for? What are we missing?

And I have asked the question before without ever getting an answer: IS THERE ANY DOCUMENTATION OR SOURCE CODE OF THIS MAGIC BLACK BOX CALLED SOFTDEVICE AVAILABLE?

Any help would be appreciated.

Regards,

[Jørgen Holmefjord]

Hi,

The documentation for the softdevices can be found here. Source code is not available.

If you are in doubt if the issue is caused by an issue with the crystal, try changing the project to use the internal RC oscillator. If there is a crystal problem, this test will tell you.

Best regards,
Jørgen

[Hugo Habicht]

Hi Jørgen,

for a test to confirm / rule out the crystal the rc would work but my understanding is that it is not accurate enough for BLE. Is that correct?

Regards,

[Jørgen Holmefjord]

The RC oscillator is accurate enough to be used for BLE after calibration, see Clock source in the softdevice documentation.

Just make sure you set the softdevice clock config accuracy to 500PPM, and use the CTIV and TEMP_CTIV configs from above link.

The drawback of using the RC oscillator, compared to the crystal, is higher current consumption due to the lower accuracy and need for calibration.

[Hugo Habicht]

Hi Jørgen,

changed to the RC oscillator but that did not make a difference. Could have guessed that before because the oscillator init is done in main().

In my case the softdevice is hanging BEFORE reaching main() (see first post).

So since your documentation contains nothing about what is happening inside the softdevice (only API) you have to help me on that one. Any ideas? What is it waiting for in address 0x2ff6?

I believe it has to be hardware related because the software (basically the BLE hrs example) is running fine on the Nordic EVM.

Regards,

p.s.: seems to be waiting for something to happen in bit 4 of a register on address 0xe000e204 which is not documented (another Nordic black box or I am too stupid to find it).

[Jørgen Holmefjord]

Which SDK and softdevice versions are you using? Is this a "clean project" from an SDK release, or something you have ported from a previous SDK version?

0xE000E204 is not a "Nordic Black Box", this is one of the ARM Cortex M4 NVIC_ISPR (Interrupt Set-Pending Registers) registers.