Matrix user forums

Hi everyone,

I just wanted to know the difference between a global array and local array on microcontrollers.
I tried to create an array of 82 bytes within the main, but the compiler (mikroC compiler, not tried on flowcode) tells me that there isn't enough memory, but creating that same array as global (outside main) does compile perfectly.

I'm just curious about why it compiles when it's a global array and why it doesn't when it's a local ?

Thanks,

Nicolas Lopez F.

Hello,

I've never used the mikroC compiler so I can't say for sure but maybe there is some wierd kind of paging going on where the compiler is trying to fit each function into a single page of memory? With Microchips C18 compiler you have to specify if the code is going to go into an alternate page or the code simply does not work but does not give you a warning or an error. I have not seen this problem in the BoostC or HiTech compilers

Ok, thanks for clarifying that ^^

The Microchip C18 compiler does the allocation using pragma commands like this.

#pragma udata1
#pragma udata2
#pragma code

The udata1 and udata2 sections contain global variables and the code section contains the functions for the program.

Thx, but I'll use Flowcode
It's easier with it.