topic Re: ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS in MCX Microcontrollers

ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS

gvellet — Wed, 26 Mar 2025 18:04:59 GMT

Hi,

With SDK example projects or new projects created from scratch, the ISP mode is not working when a valid application is in Flash.

I have traced the problem to the file startup/startup_mcxc444.c. At line 53, the struct "Flash_config[3]" is set to value 0xFFFF3FFE. The byte value 0x3F correspond to the FOPT (Flash option register) where bit 1 (BOOTPIN_OPT) = 1. This setting disable the ISP_MODE pin 26.

I have changed the byte value to 0x3D. Now when I press Reset and ISP_MODE together, the MCXC444 enters ISP mode every time.

My question is about MCUXpresso. I don't think it is a good practice to manually edit "startup_mcxc444.c", is there a project settings to customize the Flash_config value in "startup_mcxc444.c"?

Thanks

Re: ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS

diego_charles — Thu, 27 Mar 2025 22:11:52 GMT

Hi @gvellet

Thank you for your interest and for sharing the solution to the problem you encountered.

I confirm that there are no project options, to avoid manually customizing the Flash_config structure, available in MCUXpresso IDE.

Diego

Re: ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS

diego_charles — Wed, 09 Apr 2025 17:55:33 GMT

Hi @gvellet

I just want to follow up our thread with the below information!

We just released MCUXpresso Secure Provisioning Tool v25. I believe the tool provides security settings for the MCX C that you could find really useful. Below an ilustrative image, where I changed the MCU Life cycle from Unsecure to Flash secure.

As you can see in the BCA/FCF settings, the FSEC setting enabled according to Flash secured life cycle.

The SPT, for short. creates bootable and secure images, you can provide a sample image for the MCX C or your custom image. The tool requires connection to the MCU over USB/UART.

For more details about the SPT use, please refer to sections:

6.10 MCX C041/C242/C444 device workflow

6.10.3.3 Life cycle for MCX C041/C242/C444 devices

of the MCUXSPTUG , you can get it easily by doing this:

We can conclude that you can manually edit flash security settings for the MCU using the MCUXpresso IDE, however, we leveraged this to the MCUXpresso Secure Provisioining Tool

hope this helps you,

Diego

Re: ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS

gvellet — Wed, 09 Apr 2025 20:55:07 GMT

Hi Diego,

Thank you for the information and remembering my question. I will try this new software asap!

Re: ISP MODE NOT WORKING BY DEFAULT WITH FRDM-MCXC444 PROJECTS

diego_charles — Wed, 09 Apr 2025 21:30:50 GMT

Hi @gvellet

My pleasure, we just release it yersterday, please give it a try! Feel free to create another post, if you get any questions or feedback regarding the SPT. The MCX C support was just introduced.

All the best,

Diego