About interrupt preemption of MPC5604

[ningwang]

         Hello, I meet a problem about interrupt preemption of mpc5604 these days.  Our system has many interrupts, such as iic receive, uart receive, pit interrupt and so on . I set the uart interrupt priority to 5, which is higher than iic with 3, but when I debug, the uart interrupt can't preempt the iic's interrupt leading to it miss receiving some uart bytes. 

        In the reference manual, it says a higher priority can preempt lower priority. But are there any setting for it?

Thanks very much.

[martin_kovar]

Hi,

the feature, you are looking for is called Nested Interrupts.

Download following project and check file IntcInterrupts.c. There is defined macro INTC_NESTED_INTERRUPTS which is by default 0. This means that nested interrupts are not enabled and it is not possible to preempt executed interrupt.

If you set INTC_NESTED_INTERRUPTS to 1, interrupt with higher priority can preempt interrupt with lower priority.

https://community.nxp.com/docs/DOC-329441 

If you have any other question, please feel free to write me back.

Regards,

Martin

[ningwang]

Thank you very much ! It helps a lot !