SRAM

[gaetanoanania]

Hi all,

I am working with TWR K70. I would need to use the external SRAM (ext RAM of the tower) like the internal RAM  to allocate variables without direct addressing.

I mean I want to define a macro (#define XDATA) that allocates the variable in exeternal RAM.

At moment I allocate the variable in a specific address of external RAM

int*test1=(int*)ADDR1;

float*test2=(float*)ADDR2;

where ADDR1 and ADDR2 are calculated before to avoid overwritten.

I want to have the below situation:

(maybe it need previous section define in *.lcf file)

#define ADDRESSING   ...something...

int ADDRESSING test1;

float ADDRESSING test2;

so the variable will be allocated in external RAM "automatically".

Is it possible to do it?

Thanks in advance.

Gae

[Carlos_Musich]

Hi Gae,

You need to manipulate the linker file (.lcf if you are using Freescale compiler or .ld if you are using GCC)  to create an external RAM memory segment and a new section where you are going to place the relocated data. The attached document explains how to do this with GCC.

In both cases you need also to use a compiler directive in the source file to tell the compiler which are the variables that are being relocated in external RAM. The document shows how to do this with a function. With variables you can follow the same procedure.

Regards,

Carlos

[gaetanoanania]

Hi Carlos,

thank you. I think your advice will be useful a lot. I 'll let you know .

Gae