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Chapter 17
Interrupt/Exception Processing Function
User’s Manual U16702EE3V2UD00
17.2.3 NP
flag
The NP flag is a status flag that indicates that non-maskable interrupt servicing is under execution.
This flag is set when a non-maskable interrupt request has been acknowledged, and masks non-mask-
able interrupt requests to prohibit multiple interrupts from being acknowledged.
Figure 17-4:
NP Flag Format
17.2.4 Eliminating noise on NMI pin
The NMI pin has a noise eliminator that eliminates noise using analog delay. Unless the level input to
the NMI pin is held for a specific time, therefore, it cannot be detected as an edge i.e., the edge is
detected after specific time.
The NMI pin is used to release the software STOP mode. Because the internal system clock is stopped
in the software STOP mode, digital noise elimination (over-sampling) by the system clock is not imple-
mented.
After reset: 00000020H
31
8
7
6
5
4
3
2
1
0
PSW
0
NP
EP
ID
SAT
CY
OV
S
Z
NP
Non-maskable interrupt servicing status
0
No non-maskable interrupt servicing
1
Non-maskable interrupt currently being serviced
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