When a device interrupt occurs, how does the processor determine which device issued the interrupt?

[haricharanreddy]

Hi All,

While studying The interrupt module in Datasheet of MC9S12XEP100 family 

I had This Doubt " How Interrupt control module decides which interrupt has occured? when Interrupt happens."

For Example 

" If Timer Interrupt occurs How INIT module find this Interrupt was caused by Timer Module ?"

Data Sheet: https://www.nxp.com/docs/en/data-sheet/MC9S12XEP100RMV1.pdf 

Thanks in Advance :smileyhappy:

Regards

Haricharan

[danielmartynek]

Hi,
You can refer to the reference manual of the core:
CPU12/CPU12X - Reference Manual

But the description is rather generic:

Basically, the interrupts must be locally enabled and their interrupt flags must be set to be recognized as pending.
In such a situation when an interrupt triggers but its flag is cleared before its vector is fetched and there is no other interrupt pending, the spurious vector is fetched instead.

Regards,
Daniel