nrf52832 device reset

[HJLee]

I read several posts on devzone and figured out a workaround for errata 220.
I am going to test this after applying it.
But the test takes time. So, I would like to hear the answer first.
What happens when the errata 220 is triggered?

Currently, some of my ble devices are reset while in use.
When I read the reset register, there is nothing, so I am guessing it is POR or BOR.
However, it is difficult to reproduce in multiple tests.

Is there a chance it will reset when the errata 220 is triggered?

[Simonr]

Hi

The consequences of Erratum 220 is that the address of the next instruction is not written to the stack. In stack frame, the link register is corrupted.

Best regards,

Simon

[HJLee]

I understand your answer.
Could you tell me about the secondary situation that could occur due to the symptom?

I don't know much about softdevices.
But I know the errata 220 is triggered in the softdevice.
Here's the information I got from the link below.
devzone.nordicsemi.com/.../nrf52832-errata-220-clearification

So I would like to know if the symptoms of mcu reset that I am experiencing can be caused by errata 220.

[Simonr]

Hi

I'm not entirely sure what "secondary situation" you're referring to. Do you mean the sd_app_evt_wait call is used to go to sleep in your application, and that you see that the link register is corrupted during wake-up? What SoftDevice version are you using in your application? 

Best regards,

Simon

[HJLee]

The softdevice being used is s132_nrf52_6.1.1, and sd_app_evt_wait() is called to enter the sleep mode.
But I'm not sure if this is causing a link register error.

I just want to know if the errata 220 can cause a device reset.
I am seeing a reset on some devices and I would like to know if this is related to the errata 220.

[Simonr]

Hi

I discussed this with a colleague, and this MCU reset could be connected to this erratum if one of the below two cases cause it:

1. The corrupted link register points to the address in code memory where a reset is executed.

2. The corrupted link register points to a garbage value with an illegal instruction causing a hardfault and the hardfault handler does the MCU reset explicitly.

In any case, it should be possible to detect the reset cause by looking into the reset reason register (1. Soft reset, 2. hardfault).

Best regards,

Simon