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How to debug hard faults on ARM Cortex-M4?
Debugging Hard Fault & Other Exceptions on ARM Cortex-M3 and ARM Cortex-M4 microcontrollers Introduction The ARM Cortex-M core implements a set of fault exceptions. Each exception relates to an error condition. If the error occurs, the ARM Cortex-M core stops executing the current instruction, and branches to the exception’s handler function.
What does a 0 mean on ARM Cortex M7?
A 0 indicates that the target is 32-bit ARM code and a 1 indicates that the target is Thumb code. It appears that the problem was that the values in the vector table were even (indicating to the processor that the vectors pointed to 32-bit ARM code).
What happens when an exception occurs in ARM Cortex M?
The ARM Cortex-M core implements a set of fault exceptions. Each exception relates to an error condition. If the error occurs, the ARM Cortex-M core stops executing the current instruction, and branches to the exception’s handler function.
Where are the fault registers on a Cortex-M MCU?
All MCUs in the Cortex-M series have several different pieces of state which can be analyzed when a fault takes place to trace down what went wrong. First we will explore the dedicated fault status registers that are present on all Cortex-M MCUs except the Cortex-M0.
Why does GCC not work in Cortex M3?
The -mthumb switches gcc and the assembler into “thumb” mode – they will generate arm mode instructions per default, which do not work on Cortex M3. Since there is no ARM mode, we don’t need ARM/Tumb interworking, thus -mno-thumb-interwork. The compiler needed -mfpu=vfp -msoft-float for floating point support.
Is there a floating point Cortex M3 core?
Cortex M3 has no hardware floating point AFAIK, at least I am not aware of any silicon that has both Cortex M3 and floating point in hardware. There are some Cortex M4 that have. Most Cortex M3 need -mfix-cortex-m3-ldrd, this is in the errata documentation for the Cortex M3 core versions.