RE: Hard vs. Soft Reset, regarding the bootloader + RAM off

Roiger — Tue, 06 Apr 2021 14:49:00 GMT

OK, thanks Einar!

RE: Hard vs. Soft Reset, regarding the bootloader + RAM off

Einar Thorsrud — Tue, 06 Apr 2021 13:37:37 GMT

Hi,

[quote user=""]1) Is my conclusion correct in that the call to APP_ERROR_CHECK triggered a hard reset?[/quote]

No. The default SDK error handler will trigger a soft reset via NVIC_SystemReset().

[quote user=""]2) Will all assertions/faults on a release board lead to a hard reset, resetting the RAM and allowing the bootloader --> app sequence to run w/o taking the battery out of the board and putting it back?[/quote]

No. There is no reset that clears RAM explicitly (see reset behavior: "The RAM is never reset, but depending on a reset source the content of RAM may be corrupted."). The only way to confidently clear the RAM is to power-cycle the device or clear (parts of) the RAM from SW.

[quote user=""]3) The assumed hard reset after this call takes a pretty long time - around 3-3.5 minutes. Any idea why this is? Could it be because we use a watchdog?[/quote]

I do not see how that would be related.

[quote user=""]4) Besides our calls to soft resets via sd_nvic_SystemReset, are there any other soft resets initiated by the SD that we should be aware of to turn on the turned off RAM beforehand?[/quote]

The SoftDevice will not to a reset by itself, so if you have a soft reset, it is because your code (including any SDK code) does it. I cannot say which part of the SDK is relevant for you, but you can see all relevant parts by searching for NVIC_SystemReset() and sd_nvic_SystemReset() in the SDK code.