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RE: How do I allocate EX memmory in the flash targe t model.

Started by Estevam Fabio-R49496 August 5, 2003
Hi,

Please find attached a linker.cmd file that allows you to run an application
from flash and access data from both internal (x:0x40 - 0x660) and external
memory (x:0x2000 - 0xDF80) in the 805.

The difference between this file and the original linker.cmd for the 805 Flash
target is the inclusion of the following section:

#*******************************************************************************
.DataForExtDataRAM :
{

# .bss sections

* (extram.data)
* (extram.bss)

} > .xExtRAM
#*******************************************************************************

When you want variables to be placed in External Memory you can define them in
the ExternBuffer.asm file (also attached) and then you can reference them in
your C file. Dont forget to use extern. For example: for the variables defined
in the ExternalBuffer.asm file you will need to use:

extern UWord16 Buff1[1000],Buff2[2000];
extern UWord16 Int1;

Best regards,

Fabio Estevam
-----Original Message-----
From: embeddeddes [mailto:]
Sent: ter-feira, 5 de agosto de 2003 14:02
To:
Subject: [motoroladsp] How do I allocate EX memmory in the flash target
model. I am presently developing a program for the DSP56F805EVM using
Codewarrior 5.1 with the Motorola embedded SDK. The final project
requires that the program be stored in internal flash memory. I am
therefore using the FLASH target when sending my code to the EVM.
My major concern right now is that the 805 has only 2K of data ram
and my program will need to allocate more than this limit. When I
set the target to external memory, I have roughly 49 K-Words of data
memory located on the external bus. By looking at the linker
command files for each target, I see that the external memory
configuration sets the (mode = 3) and the (EX = 0), while the
internal memory configuration set the (mode = A0) and the (EX = 0).
I believe that I need a third configuration that allows me to
allocate external memory. I am unsure of how this works and any
help or information would be appreciated.
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linker_example.zip
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