3.5 Interrupt Vector Table (IVT) Remapping

The dsPIC33A family of devices implements a remappable interrupt vector table (IVT). This allows boot code to use hardware peripheral interrupts natively during start-up, then hand off the interrupt control to another application by updating the value of IVTBASE prior to execution.

Remapping the IVT via the IVTBASE provides a potential attack surface that could be used to change application behavior by intercepting interrupts remapping them to another location in memory. To prevent tampering, IVTBASE can be made read-only by setting the IVTBASELK bit. This will lock the IVTBASE value until the next Reset.