how to write a link cmd file for DM642?

I just begin a project of DM642 and I don't know why the link cmd file
is needed and how to write it. I think that,  as gel file has already
define the memory map, why the link.cmd is still needed?

On 17 Mar 2006 19:52:55 -0800, "X.Y." <Xieyu1219@gmail.com> wrote in
comp.dsp:

> I just begin a project of DM642 and I don't know why the link cmd file
> is needed and how to write it. I think that,  as gel file has already
> define the memory map, why the link.cmd is still needed?

The gel file tells the debugger about the memory map.  It doesn't tell
the linker anything.  You need to tell the linker where the memory is
in your particular model of the DSP part, and you also have to tell it
where to put different parts of your program, the code, the variable
data, the constant data, the stack, and so on.

Code Composer Studio should come with some sample programs that
include cmd files.  Also go to http://www.dspvillage.ti.com and look
up your DSP.  There should be more sample programs, with cmd files,
that you can download.

You may need to look at the data sheet for your chip model to figure
out where all the memory spaces are.

-- 
Jack Klein
Home: http://JK-Technology.Com
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Thanks a lot for your reply. I should read the document of my chip...

"X.Y." <Xieyu1219@gmail.com> wrote...
> I just begin a project of DM642 and I don't know why the link cmd file
> is needed and how to write it. I think that,  as gel file has already
> define the memory map, why the link.cmd is still needed?

As Jack Klein wrote: the GEL is mainly for the debugger.

When you use Code Composer Studio (CCS) you don't need to create a *.cmd
file yourself.

In CCS: set up a project, include the DSP/BIOS group to setup the memory
regions etc. See the tutorial, project set up, DSP/BIOS settings.
A cmd file for the linking phase is generated automagically. After a build
you can find the generated .cmd file in your project directory.

Only if you do need specials things like a host loading the DSP through the
HPI bus, you may have to ADD a small .cmd file of your own, that will be
used TOGETHER with the DSP/BIOS project generated .cmd file. See the
examples used for generating HEX files using the HEX6X utility.

Regards,
Arie de Muijnck