CHAPTER 7 INTERRUPTION/EXCEPTION PROCESSING FUNCTION
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User’s Manual U14359EJ4V0UM
7.2.3 Non-maskable interrupt status flag (NP)
The NP flag is a status flag that indicates that non-maskable interrupt (NMI) servicing is under execution.
This flag is set when an NMI interrupt has been acknowledged, and masks all interrupt requests and exceptions to
prohibit multiple interrupts from being acknowledged.
31
0
PSW
After reset
00000020H
7
NP
6
EP
5
ID
4
SAT
3
CY
2
OV
1
S Z
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit position
Bit name
Function
7
NP
NMI Pending
Indicates whether NMI interrupt servicing is in progress.
0: No NMI interrupt servicing
1: NMI interrupt currently being serviced
7.2.4 Noise elimination
NMI pin noise is eliminated with analog delay. The delay time is 60 to 300 ns. A signal input that changes within
the delay time is not internally acknowledged.
7.2.5 Edge detection function
External interrupt mode register 0 (INTM0) is a register that specifies the valid edge of a non-maskable interrupt
(NMI). The NMI valid edge can be specified to be either the rising edge or the falling edge by the ESN0 bit.
This register can be read/written in 8-bit or 1-bit units.
Address
FFFFF880H
7
0
INTM0
6
0
5
0
4
0
3
0
2
0
1
0
<0>
ESN0
After reset
00H
Bit position
Bit name
Function
0
ESN0
Edge Select NMI
Specifies the NMI pin’s valid edge.
0: Falling edge
1: Rising edge