CodeWarrior for MCU中的主题 Re: Defining a functions location in ROM

Defining a functions location in ROM

hard_wired — Sat, 06 Oct 2007 02:27:52 GMT

I have the need to place an interrupt's function body at a predefined address in ROM.

How would I go about doing this in C?

- Mike

Re: Defining a functions location in ROM

Nabla69 — Sun, 07 Oct 2007 04:40:07 GMT

Hello,

Have you tried like for variables ?

void function(void) @ 0x4500; // prototype

#PRAGMA CODE_SEG SPECROM
void function(void); // prototype
#PRAGMA CODE_SEG DEFAULT
(...)

#PRAGMA CODE_SEG SPECROM
void function(void) {
blabla;
}
#PRAGMA CODE_SEG DEFAULT

with SPECROM declared in your PRM file.

Alfreda

Re: Defining a functions location in ROM

CompilerGuru — Sun, 07 Oct 2007 20:44:54 GMT

The @ syntax is not supported for functions as far as I know,
but the #pragma CODE_SEG should work.
For a HC12/S12/S12X (not sure about the CPU of the OP), its usually enough to place interrupt handlers anywhere in a non paged region. For this there is already an existing section (I think its called NON_PAGED. but I'm not sure). Also I would add a __NEAR_SEG qualifier for the HC12 to the #prama.

Daniel

Re: Defining a functions location in ROM

CrasyCat — Mon, 08 Oct 2007 16:09:35 GMT

Hello

Just to close the loop here.

I agree with CompilerGuru. @ operator is not applicable to functions.

So you have to place the function in a specific section.

The section NON_BANKED is used is standard project to place code which needs to be allocated in the non-paged ROM area.

And you need to write the pragma as

#pragma CODE_SEG __NEAR_SEG NON_BANKED

I hope this helps.

CrasyCat