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What is hard fault in Cortex M3?
Hard Fault: is caused by Bus Fault, Memory Management Fault, or Usage Fault if their handler cannot be executed. After reset, not all fault exceptions are enabled, and with every fault the Hard Fault execp- tion handler is executed. Cortex-M vector table.
What is hard fault in arm?
A hard fault is an exception that occurs because of an error during normal or exception processing. As per the Cortex-M0 Devices Generic User Guide (revision r0p0), the following sources can cause a hard fault: execution of an SVC instruction at a priority equal or higher than SVCall.
How to debug hardfault on an ARM Cortex-M MCU?
This can be done by setting bit 1 ( DISDEFWBUF) of the register to 1. For the Cortex M7, there is no way to force all stores to be synchronous / precise. This register only exists for Cortex-M7 devices. When an IMPRECISE error occurs it will at least give us an indication of what memory bus the fault occurred on 4:
What does vecttbl mean on ARM Cortex-M MCU?
VECTTBL – Indicates a fault occurred because of an issue reading from an address in the vector table. This is pretty atypical but could happen if there is a bad address in the vector table and an unexpected interrupt fires. To fix a fault, we will want to determine what code was running when the fault occurred.
What does divbyzero mean on an ARM Cortex M MCU?
Fields are only cleared by a system reset or by writing a 1 to them. This register is a 2 byte register which summarizes any faults that are not related to memory access failures, such as executing invalid instructions or trying to enter invalid states. DIVBYZERO – Indicates a divide instruction was executed where the denominator was zero.
What happens when a hardfault is run on an ARM processor?
Once in the HardFault Handler, the ARM Core is operating at a non-configurable priority level, -1. At this level or above, a fault will put the processor in an unrecoverable state where a reset is expected. This state is known as Lockup.