topic MCXN user Registers in MCX Microcontrollers

MCXN user Registers

VGJ — Fri, 11 Oct 2024 08:01:34 GMT

Hi everyone

I'm testing with the FRDM-MCXN947 development board. For my application I need to save a unique 8-byte number as a constant somewhere in the flash on the first boot. I had thought about the GPREG registers but I don't know if it's possible and if it would conflict with other functions of the micro. Could you tell me if there is a small free space in memory for the user program?

Thanks in advance
Victor

Re: MCXN user Registers

Alice_Yang — Sat, 12 Oct 2024 07:42:27 GMT

Hello @VGJ

The register GPREG is used within the PowerQuad MAC engines. How about using the last few bytes of flash?

Alice

Re: MCXN user Registers

VGJ — Mon, 14 Oct 2024 13:43:52 GMT

Hi Alice, thanks a lot for your help.

I would prefer not to have to reserve space on the Flash, especially since I'm going to use dual-bank mode and don't want to complicate the structure for such a small space. I won't be using the RTC in principle, could I use the alarm logs for this purpose?

Thanks and best regards

Re: MCXN user Registers

Alice_Yang — Wed, 16 Oct 2024 09:08:26 GMT

Hello @VGJ

Could you please describe more about your application purpose？

What application do you want to use this space for?

Alice

Re: MCXN user Registers

VGJ — Wed, 16 Oct 2024 09:37:25 GMT

Yes, of course. In the manufacturing process of our devices, more specifically in the test phase, if everything has worked correctly, a unique 8-byte number is recorded to the micro via uart. Thus, at the next start-up it goes into working state.

In our previous design we used an LPC1778 and we had an internal EEPROM that we used for this purpose. We even used some RTC registers for other purposes since it offered a lot of flexibility.

But this series lacks an internal EEPROM and we do not want to use the program flash to store this simple number. We are also interested in that this number is stored in the uC itself and not in an external EEPROM that can be manipulated

I hope this explanation can guide you in what we are looking for

Thanks and best regards
Victor

Re: MCXN user Registers

Alice_Yang — Wed, 23 Oct 2024 07:20:53 GMT

Hello @VGJ

If you can implement it using the RTC on the LPC1778, you can also use the RTC of the MCXN.

Alice