CHAPTER 8 INTC
Preliminary User’s Manual A14874EJ3V0UM
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8.2.1 Operation
If a non-maskable interrupt is generated according to DCNMIn input, the CPU performs the following processing
and shifts control to the handler routine (n = 2 to 0).
<1> Save the restored PC in the FEPC.
<2> Save the current PSW in the FEPSW.
<3> Write the exception code in the higher halfword (FECC) of the ECR.
<4> Set the NP and ID bits of the PSW and clear the EP bit.
<5> Set the handler address for the non-maskable interrupt in the PC and shift control.
Figure 8-2 shows the processing format of non-maskable interrupt service.
Figure 8-2. Non-Maskable Interrupt Processing Format
Non-maskable interrupt
request
FEPC
←
Restored PC
FEPSW
←
PSW
ECR.FECC
←
Exception
code
PSW.NP
←
1
PSW.EP
←
0
PSW.ID
←
1
PC
←
Handler
address
0
PSW.NP
INTC
acknowledgement
CPU processing
1
DCNMIn input
Interrupt service
Interrupt request pending