RAM 6.0 BUX II Series Guia do Utilizador descarregar pdf (Página 129)

4 Debugging Your BSP

4.2 Basic Debugging Techniques

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Looking at the disassembly of an object file is helpful when, given the address of

an exception, you need to find out where the exception took place in your code.

The following command is helpful in this situation:

objdumparch --disassemble-all --show-raw-insn tmp.o

Finding Addresses in RAM

The previous sections describe several ways to determine what should be in RAM.

However, this information must be correlated with what is actually there. The

easiest way to do this is to connect an on-chip debugging (OCD) device to your

target, then set a hardware breakpoint at the RAM entry point, and use the OCD

device to examine memory. Without the OCD device, determining what is in RAM

is more difficult.

If a vendor-supplied ROM monitor is available, it may be possible to use the ROM

monitor to load the application and then check the contents of RAM. If two flash

banks are available, the VxWorks image can be programmed into the other flash

bank and examined from the ROM monitor. Finally, if the ROM monitor provides

hardware breakpoint support, it may be possible to set a hardware breakpoint at

the RAM address and then start executing the VxWorks boot application. When

the breakpoint is reached and execution stops, the memory can be examined using

the ROM monitor.

If no ROM monitor is available, it may still be possible to do some debugging.

During the initial phases of BSP development, when the BSP consists only of LED

code, the entire image may fit into a small bank of NVRAM. After the system boots,

this memory can be removed from the system and read on another system.

4.2.3 Verifying RAM

The section discusses how to verify RAM.

Runtime Execution

At this point, you are building an image and programming the flash with it. The

image is located in the correct area and you are ready to power on and run the boot

ROM code. You now need a way to debug the runtime image. The following

discussion assumes that you do not have an OCD device, but you do have at least

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RAM 6.0 BUX II Series Guia do Utilizador Página 129