CHAPTER 7 INTERRUPTION/EXCEPTION PROCESSING FUNCTION
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7.2.1 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 (00000010H) corresponding to the non-maskable interrupt to the PC, and
transfers control.
The servicing configuration of a non-maskable interrupt is shown in Figure 7-1.
Figure 7-1. Servicing Configuration of Non-Maskable Interrupt
PSW.NP
FEPC
FEPSW
ECR.FECC
PSW.NP
PSW.EP
PSW.ID
PC
Restored PC
PSW
0010H
1
0
1
00000010H
1
0
NMI input
Non-maskable interrupt request
Interrupt servicing
Interrupt request held pending
INTC
acknowledged
CPU processing