S32K3 Vector Table Alignment

[kscz]

The ARMv7 architecture reference manual says that the vector table needs to be aligned as follows:
 

The S32K3xx chips have an "image vector table" which is 256 bytes:

if the ARM vector table immediate follows the "image vector table", this alignment is not naturally maintained. Do I need to put in padding bytes such that the alignment of the ARM vector table follows the guidance of the architecture reference manual?

[PetrS · Accepted solution]

Hi,

yes, for S32K3 devices, the vector table must be aligned according to the ARM Cortex‑M7 VTOR rules - that is, aligned to the size of the vector table, usually a power‑of‑two boundary (e.g., 0x1000). If the linker places the table at an address that does not meet this requirement, VTOR writes may appear to work, but exception entry can fault due to misalignment. In many S32K3 startup files, the table is copied to RAM (to be able change IRQ handler address in runtime) and VTOR is updated,  so the RAM placement also must respect this required alignment. Ensuring the linker script aligns the vector table section correctly typically resolves the reset/exception alignment problems.

BR, Petr