MSP430G2855: Determining size of stack and heap

Doug Broadwell85

Part Number: MSP430G2855

I'm running out of ram and want to find the actual amount of RAM used for the stack and the heap. It looks like it would be the easiest to fill the stack and the heap with a pattern, run the program, and look at the memory. I've looked at the literature on the _system_pre_init() but can't figure out how to use it - do I write that function at the start of my main.cc file? Put it in a separate file and somehow tell the linker to load it and not the default one in pre_init.c?

I am no longer using the console for I/O, using the UART instead so don't need CIO, but I am using functions like sprintf() but don't know if it or anything else from the standard libraries use the heap.

Any help would be appreciated.

Thanks, Doug Broadwell

over 2 years ago

0 Xiaodong LI over 2 years ago

TI__Mastermind 23295 points

Please check MSP430 Optimizing C/C++ Compiler v21.6.0.LTS User's Guide (Rev. Y)

This document is helpful to introduce the stack, stack point and the _system_pre_init()

Thanks!

0 Doug Broadwell85 over 2 years ago in reply to Xiaodong LI

Intellectual 540 points

Yes, I'm afraid I've read it a bunch, but sorry to say that I still can't work out the details, possibly need to dive more into the linker?

Thanks

Doug

0 Doug Broadwell85 over 2 years ago in reply to Xiaodong LI

Intellectual 540 points

One of my main issues is: where to put my "int _system_pre_init(void) {}" code; do I just put it somewhere in the file that contains "int main(void)" ?? If I put in "int _system_pre-init(void) { return(1); };" I get ' "../main.cc", line 194: error #66: expected a ";" '.

0 Bruce McKenney over 2 years ago in reply to Doug Broadwell85

Guru 100735 points

The short answer: Yes, just stuff it into main.c somewhere.

---

> int _system_pre-init(void) { return(1); };

This looks like a typo ("-" instead of "_"). Or maybe it's objecting to the trailing ";"? Try:

> int _system_pre_init(void) { return(1); }

---

I haven't intruded since I haven't done this (on an MSP430). If your current plan doesn't work out, you might get something from the ",fill=" option in the SECTIONS ".stack" and ".sysmem" part of the linker .cmd file. It will make your executable bigger, but you can remove it once you have your answer.

0 Doug Broadwell85 over 2 years ago in reply to Bruce McKenney

Intellectual 540 points

Man I hate it when I make stupid mistakes in front of everyone !

Thanks Bruce.

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MSP430G2855: Determining size of stack and heap