RAM 6.0 BUX II Series Guia do Utilizador descarregar pdf (Página 57)

2 Overview of a BSP

2.4 The Development Environment

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It must be able to generate code that works with the debugger, if any, that is to

be used for BSP development. It should also work with the debugger(s) that

will be used during application development.

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It must not generate code that silently performs certain activities such as

memory allocation. For example, no BSP code or driver code should be written

using C++ because the C++ compiler does silent memory allocation to allocate

constructors, as well as other tasks that are not available until after the OS is

completely booted or that cannot be done during ISR execution.

Also keep in mind that the BSP is recompiled often, and that the BSP may be

compiled with a different compiler than the one that is used for development. For

portability, it is wise to insure that the compiler is used with the most stringent

options available, such as the -ansi -pedantic flags of the GNU compiler.For more

information, see the Wind River C coding standards in the VxWorks Hardware

Interface Validation Guide.

To find out what compiler and linker flags are required, go to your reference BSP

and build one of the standard VxWorks image types. Typically, this is vxWorks (a

RAM image) or vxWorks.res_rom_nosym (a flash image).

There are also ancillary tools, such as an archiver, disassembler, linker, binary file

dump program, and so on. These tools should be available as part of the package

that the compiler comes with or as part of the debugger. If the package that is

chosen is missing a tool, a compatible version of that tool may be available from

some other source. For example, if a program to display object module symbols is

missing, you can use the nmarch program (nmppc or nmarm, for example) that is

part of the Wind River IDE installation.

2.4.5 Download Path

The following are some of the more common techniques for downloading code to

the target during BSP development:

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Use the download protocol supplied in the board vendor’s debug ROMs. The

drawback of this approach is that downloading is often slow. The advantage is

that it is easy to set up.

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Program the image into ROM. This allows code to be put onto the target, but

does not allow any mechanism for debugging other than the LED or kprintf( )

routines (see Primitive Tools, p.44). However, debugging the LED or kprintf( )

routines is extremely difficult if this is the download mechanism.

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RAM 6.0 BUX II Series Guia do Utilizador Página 57