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Chapter 5
Interrupt Controller (INTC)
Preliminary User’s Manual U17566EE1V2UM00
5.2.1
Operation
If a non-maskable interrupt is generated, the CPU performs the following
processing, and transfers control to the handler routine:
(1) Saves the restored PC to FEPC.
(2) Saves the current PSW to FEPSW.
(3) Writes exception code 0010H to the higher halfword (FECC) of ECR.
(4) Sets the NP and ID bits of the PSW and clears the EP bit.
(5) Sets the handler address corresponding to the non-maskable interrupt to
the PC, and transfers control.
The processing configuration of a non-maskable interrupt is shown in
Figure 5-3
.
Figure 5-3
Processing configuration of non-maskable interrupt
Non-maskable interrupt
request
FEPC
←
Restored PC
FEPSW
←
PSW
ECR.FECC
←
Exception
code
PSW.NP
←
1
PSW.EP
←
0
PSW.ID
←
1
PC
←
NMI-Handler
address
0
PSW.NP
INTC
acknowledgement
CPU processing
1
NMI input
Interrupt service
Interrupt request pending
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