Using memory efficiently

Forum 2005-2010 (read only) Software Development
#1

I'm a little hazy on the memory usage in the Arduino software. I have a number of independent modules that will run in sequence. Since these are pretty independent, in a normal programming environment I'd conserve memory by utilizing the stack as much as possible, e. g. make each module a function with local variables on the stack.

So the question is, does this model work on the Arduino? Is there also a heap?

Thanks, Jim.

#2

For the AVR processor that uses the Harvard architecture, variables and stack are both located in the same SRAM memory so in reality using global variables would decrease SRAM usage I would think.

Lefty

#3

Re: Using memory efficiently Reply #1 - Today at 17:20:43 For the AVR processor that uses the Harvard architecture, variables and stack are both located in the same SRAM memory so in reality using global variables would decrease SRAM usage I would think.

Lefty

I agree. I was just wanted to be sure the stack exists and goes away at the end of a function. If I need 100 bytes of memory in 200 different functions, can I assume I'm going to get them, 100 at a time, like in conventional c environments? Or are they somehow always statically assigned?

Thanks, Jim.

#4

I was just wanted to be sure the stack exists and goes away at the end of a function

Only the current stack frame goes away at the end of the function, not the stack itself.

If I need 100 bytes of memory in 200 different functions, can I assume I'm going to get them

It depends on how the functions are nested. If they're all consecutive, then yes, you'll get them.

#5

It depends on how the functions are nested. If they're all consecutive, then yes, you'll get them.

So it behaves like a conventional C or C++ program. Thanks, that's what I wanted to be sure of.

Jim.

#6

So it behaves like a conventional C or C++ program.

Yes, and that is because it essentially is. :)

#7