Reading from flash causes hardfault

[Adomin]

I'm working with the STM32wb55ceu MCU which states that it has 512K of flash memory starting from address 0x08000000.

However, I realized that if I compile and run the follow program, it will hard fault when attempting to read the value from flash (line 3)

void main ()
{
    uint8_t i = *(uint8_t *)0x0806f18c;
    (void)i;
    while (1);
}

To my understanding, the flash should end at 0x08080000. and I have confirmed that my flash memory size is 512K by using the st-info utility.

Is there some sort of memory protection I need to disable?

[Tesla DeLorean]

If you dump the faulting address in the Hard Fault handler, what does it report?

Unwritten FLASH may fail ECC checks

[Adomin]

Looks like BusFault Status Register contains 0x82 which means BFARVALID is set and PRECISERR

if this is what you were asking

[TDK · Accepted solution]

0x0806f18c is near the end of the flash.

You're probably reading FLASH that is reserved for the second core (CPU2) handling the wireless functions.

From the datasheet:

[TDK]

Read out FLASH_SFR to verify what's reserved for CPU2.

[Adomin]

Makes sense. I missed that in the data sheet. Thank you.