Part Number: MSPM33C321A
Per ARM architecture, VTOR must be aligned to:
Alignment = Power of 2 ≥ (Number of vectors × 4)
For MSPM33C321A:
- ICTR register = 1 → Hardware supports 53 external IRQs (IRQ0-52)
- Total vectors = 16 (system exceptions) + 53 (IRQs) = 69 vectors
- Vector table size = 69 × 4 = 276 bytes
- Required VTOR alignment = 512 bytes (0x200)
If VTOR is not properly aligned, ARM specifies behavior as UNPREDICTABLE.
Even with 256B we can support only 64 vectors. However, interrupts with vector index 64+ will fail:
Affected IRQs (index 64+):
- SHAW, PKA
- UC13_1, UC13_2, UC13_3
Reference - https://documentation-service.arm.com/static/5f16e93d20b7cf4bc524af1d
