LPC55S16 RAM entries after software reset

[steffenrose]

Hello,

I want to create a unsecure secondary bootloader and want to save some byte between software reset. It seams that the location 0x20000000..0x20010000 is changed during this reset. I stoped in ResetISR() and the Debugger show different values. So it is not the clib, that initialize the data. It seams the LPC internal bootloader.

The reset is NVIC_SystemReset().

Is there a location, where I can use some Bytes that do note change? At the best a location for the hole LPC55xx family.

I use the MCU xpresso IDE and the LPC55S16-EVK at the moment. I checked the memory using the Memory window of the IDE.

[Alice_Yang]

Hello steffenrose,

How about place the data in specific memory region, refer to MCUXpesso IDE User Guide:

[steffenrose]

Thank you very much. My question was related a specific memory location. Now I learnd, that the Boot Rom use a lot. This memory is not suitable to save values during a software reset,

I think the MCUXpresso autogenerated linker scripts should prevent this location to use for the noinit sections.

Currently I use a different way.
I set a offset for the Stack location and create a section at the end using

--section-start=command=0x2000FFF0

Thats why I want, that our end customer can use the Managed linker scripts for different derivates.

Unattractive is, that objcopy use it for ihex and binary generation like the text section.

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .sec1         00008000  00008000  00008000  00000000  2**0
                  CONTENTS, ALLOC, LOAD
  1 .sec2         00007770  00010000  00010000  00016811  2**0
                  CONTENTS, ALLOC, LOAD
  2 .sec3         00000010  2000fff0  2000fff0  0002b82b  2**0
                  CONTENTS, ALLOC, LOAD

[Alice_Yang]

Hello steffenrose,

Thanks for your sharing, I will take a ticket to MCUXpresso development team about your this suggestion:" I think the MCUXpresso autogenerated linker scripts should prevent this location to use for the noinit sections."

BR

Alice

[Alice_Yang]

Hello steffenrose,

How about save your data in Flash memory? 

BR

Alice

[steffenrose]

It's short time data, that I want to use to configure the restarted device.