CC3220MODA: RAM retention during PRCMMCUReset

Katie Elliott19

Part Number: CC3220MODA
Other Parts Discussed in Thread: CC3220SF,

I need to store some variables to be retained through reset. I am using PRCMMCUReset, but I have not yet successfully been able to maintain the variables through reset. I am using CCS with makefile using GCC. It is certainly possible I have something wrong with my linker command file or elsewhere, but before spending a lot of time debugging, I just want to confirm the following:

Is RAM retained during PRCMMCUReset for the CC3220SF?

over 5 years ago

0 Hnz over 5 years ago

Guru 39650 points

Hi,

No this is not possible. RAM ise zeroed by the ROM bootloader after reset from the security reasons.

Jan

0 Katie Elliott19 over 5 years ago in reply to Hnz

Intellectual 650 points

Thank you for the quick response. I have a follow up question on how to accomplish what I need:

We need to store some event logs in case of catastrophic errors (asserts, etc). We were planning to do limited error logging in flash. However, since flash is accessed via the NWP, we can't guarantee that the NWP is in a state to be able to write to flash. So the plan had been to write to uninitialized RAM, do a reset, then write the log to flash. (I had read this: https://e2e.ti.com/support/wireless-connectivity/wifi/f/968/t/889146 which led me down that path to using PRCMMCUReset()).

Do you have any recommendations for how to accomplish this on the CC3220MODA, given that we cannot use uninitialized RAM on this processor?

Thanks,

Katie

0 Hnz over 5 years ago in reply to Katie Elliott19

Guru 39650 points

Hi Katie,

In case you want to save temporary information in case of hard fault, you have two options:

save information into additional hardware like a small EEPROM
save information into XIP flash. XIP flash is not a good storage of permanent user data, but for your purpose it can be fine - please see this example of writing into XIP flash of CC3220SF chip

Jan

0 Katie Elliott19 over 5 years ago in reply to Hnz

Intellectual 650 points

That worked, thanks very much!

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CC3220MODA: RAM retention during PRCMMCUReset