Perform soft reset without losing RAM Data on ARM cortex M4

1
votes

I am working on controller having architecture of ARM CORTEX M4. Flash of controller contains 2 different applications Boot loader and Application. I want allocated RAM section via to store some data which I will share in both boot loader and application. Problem for me is when I jump from one application to another(Reset vector) my RAM section data from which I want to persist is getting cleared. As I am new to this kind of implementation, please guide me how can I achieve such implementation where RAM data will persist after soft reset or jump from one application to another.

Thanks in advance.

1
armcortex-m
Correction : I have allocated RAM section via scatter file to store some data which I will share in both boot loader and application – raj
take over or replace the bootstrap so that it doesnt initialize memory. Note that cortex-m4 is too vague, what chip are you using (cortex-m4 is not a chip). the chip vendor may do an sram init that you cannot get around. – old_timer
I am using XMC4400 controller – raj
Which compiler do you use? – vlk

1 Answers

2
votes

This will be linker dependant, so look at the manual for your linker to see how to make a memory region not be initialised.

Depending on your microcontroller too, there may be some memory you can use, in the RTC peripheral of STM32s for instance there are some (20 x 32bit) back up registers which wouldn't be initialised and persist in low power states.