Flash Memory Write protection via MPU Configuration for LPC55XX / Cortex M33

[pejo]

Hi there,

I'm trying to protect some factory configuration in my flash memory. I thought that I could protect the flash memory from being written (when this is done using  the function LPC55S0XFLASH_Program or LPC55S0XFLASH_Erase). 

When I configure the MPUs it seems that these functions don't trigger an exception or a hardware fault of any kind as I would expect and as it happened when I try to write in those areas by standard write operations.

Can you confirm that this is how it should happend and/or provide an alternative?

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be supporting your case, what kind of part are you using? is this have an S on the making number? example LPC55s69, if yes, the other alternatives that I recommend is using a signed image. 

If you want to know more about this there are some apps note that could help you to setup.

Spoiler

LPC55S6x | Arm®Cortex®-M33 | 32-bit MCU | NXP Semiconductors

The other way is modifying the CPMA and CFPA using the Flash API or using the tool Blhost through PC Host serial interface.

Best regards,
Pavel

[pejo]

Hello Pavel,

we are using LPC5504 and LPC55S04. I'm not sure I understand your comment. How using a signed image can help protect certain data areas from flash?

How can I protect a memory section using CPMA and CFPA?

[Pavel_Hernandez]

Hello, I recommend see this links could clear more about the differences of this LPC´s.

[LPC55]: Disable ISP and SWD to utilize code protection - NXP Community

Best regards,
Pavel