Hardware flash write protection

The hardware flash write protection driver (fprotect) can be used to protect flash areas from writing. The driver uses a hardware peripheral (BPROT, ACL, or SPU, depending on the chip model) to protect the area. The protection is irreversible until a reset occurs.

The following example shows how to protect PM_B0_SIZE bytes of the flash area starting from PM_B0_ADDRESS:

int err = fprotect_area(PM_B0_ADDRESS, PM_B0_SIZE);

API documentation

Header file: include/fprotect.h
Source files: lib/fprotect/
group fprotect

API for write protection of flash areas using Hardware peripheral.


int fprotect_area(uint32_t start, size_t length)

Protect flash area against writes.

  • start[in] Start of range to protect.

  • length[in] Length in bytes of range to protect.

Returns 0

On success.

Returns -EINVAL

If any of the argument are incorrect.

Returns -EFAULT

If the protection was not applied properly.

Returns -ENOSPC

If function is called too many times. Applies to devices where there is a limited number of configuration registers which are used for all address ranges.