multiple interrupt hard fault

[EPora.1]

Hello,

I'm using an stm32f411ce in an application that includes an external interrupt, a uart DMA TF interrupt and a systick interrupt. with the external interrupt in the highest priority and the systick in the lowest respectively. The code runs for a few seconds and then goes to a hard fault. and ideas?

Thanks,

Eyal

EDIT:

Also, I have seen somewhere that it may be an unaligned memory that is causing the error so I have set the stack align bit like this:

SCB ->CCR |= (1 << 9); //set stack align

but the processor doesn't seems to get the command

and there is no button for setting it which there should be

[Tesla DeLorean]

>>any ideas?

Look at what is ACTUALLY faulting..

Instrument your code so you know what happens, and the flow involved.

Check stack depth.

Check you're not using transient buffers for DMA.

[EPora.1]

In the fault report window with ARM compiler 6 and -O1 optimization it says that it is a bus fault, specifically IBUSERR. when the optimization is at -O0 it says that it's a memory fault; IACCVIOL. Both's description says that it can be either an invalid return due to corrupted stack or an incorrect entry in the exception vector table

[simosilva]

I saw this problem many times when an incorrect IRQ enter when another one is served, causing bad push and pop in the stack, tipically resulting into a read on the address specified by some content of other registers coming from the bad pop, if this reads a protected memory region you clearly have the bus/memory hard fault.

In debug, placing a __BKPT() into the hard fault (or even into the IRQ handler that causes the fault) and then looking into the call stack you will have a more clear view.

[EPora.1]

Hello, thanks for your answer!

I have tried that and it seems that the code crashes every time on this function which is inside an interrupt routine:

void Quaternion::normalize()
{
  float n = magnitude();
  c[0] /= n;
  c[1] /= n;
  c[2] /= n;
  c[3] /= n;
}

and the fault seems to be a usage instruction error.