13.8.1 Peripheral Interrupt Vector Address

The vector address is determined by the value of the interrupt request number and the value of the base register bits. The base register - IVTBASE value is used to provide an offset for the base address of the interrupt vector, so that interrupt vector addresses can be mapped anywhere in user Flash or anywhere in the user RAM.

To calculate the address in the vector table where a particular peripheral interrupt vector resides, use the following equation:

address = (Base (Hex) + (IRQ number x4 (decimal)) + 24 (hex)

An example for Interrupt #21 with Base address = 0x80A000:

address = (0x80A000 (hex)+ (21x4 (dec)) +24 (hex) = 0x80A078 (hex)

An example for Interrupt #21 after reset:

address = (‘800000 (hex)+ (21x4 (dec)) +24 (hex) = 800078 (hex)