Hi Frank,
thank you very much for your topic Thank YOU for helping me...
Sorry that I can't help you, but possibly you could write which tools
you are using. I tried WINARM but had no success to compile anything of
the already written examples. WinAVR (wich I also use) seems to be quite
simple compared to WINARM....
I use LPC2129 with WinXP.
Thabks in advance for an answer,
Helmut



frank mx wrote:
> I started arm development with a self build board with a tms470 from ti.
> The first what I had to do was to read many documents about building an
> executable with gcc. I'm a bit expirienced with the command line tools
> and the entire build process from my development with atmels avrs. But
> with the arm development there where some new tasks. I had to provide my
> own startup code and I had to apply a appropriate linker script.
> The linker script is because of different sections which have to be
> paced on different positions in the memory of the device. The .text
> section which containes the executable code has to be placed in flash
> while the .bss section which contains uninitialized variables has to be
> placed in ram. The .data section which contains initialized data is a
> bit special. It has two addresses. One addrss (the load address or LMA)
> has to be placed in flash. This is the address, where the initial values
> are stored. This address the data section has to be loaded to on
> flashing the device. While running the processor should also be able to
> write the variables. That's why we need a second address for this
> section (the execution address or VMA). All instructions within that
> image refere only the execution adresses oft those variables. But how
> come the variables from the LMA to their VMA? Here comes the startup
> code into the game. It copies the whole .data section from its load
> address to its execution address. So far, so good, I get all fliles
> compiled and linked into one elf image. Also the map file tells me that
> the .data section has different addresses for load and execution. My
> problem now is the following:
>
> When I want to debug my very sipmle code within the simulator of the
> gdb/insight, all variables of the .data section are placed already on
> their execution addresses and the load addresses are empty (NULL). If
> now the startup code copies the .data section it overwrites the correct
> values with zeros.
> Why goes this wrong? There is nothing else target specific than the
> ioheader.
>
> Thanks in advance for your answers.

Hello Frank,

welcome on board!

I started also my arm development with the TMS470 processor.
I don't know what you mean with LMA and VMA. Couldt you explain this?

In the moment I can run and debug my own programs in the RAM of the
TMS470.
I use Eclipse as IDE and a USB-JLink-Adapter for the connection to my
development board. The connection beetween the JLink-Adapter und Eclipse
is realized with an open source gdb server. You can also use this server
for the connection to gdb/insight.
The next step is the development of the flash loader.

Ok, I hope we can exchange some information about the development for
the TMS470.
Because this is a very new processor, the information on the www is very
small.

Best regards
Karsten

frank mx wrote:

> When I want to debug my very sipmle code within the simulator of the
> gdb/insight, all variables of the .data section are placed already on
> their execution addresses and the load addresses are empty (NULL). If
> now the startup code copies the .data section it overwrites the correct
> values with zeros.

You might look into the examples for LPC2xxx. You will see that the
startup-code has some sections with #ifdef RAM_RUN (or #ifdef ROM_RUN).
Just "envelop" the .data-copy-routine with #ifdef ROM_RUN/#endif and do
not define ROM_RUN. So the coping will not be done for the
"debug-image". For a "flash-image" define ROM_RUN (-DROM_RUN) to enable
the the copy-routine for .data from flash to RAM.

Hope this helps,
Martin Thomas