CHAPTER 5 INTERRUPT/EXCEPTION PROCESSING FUNCTION
User’s Manual U13850EJ4V0UM
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5.2.3 NP flag
The NP flag is a status flag that indicates that non-maskable interrupt (NMI) servicing is under execution. This flag
is set when the NMI interrupt request has been acknowledged, and masks all interrupt requests to prohibit multiple
interrupts from being acknowledged.
Figure 5-4. NP Flag (NP)
After reset: 00000020H
Symbol
31
8
7
6
5
4
3
2
1
0
PSW
0
NP
EP ID SAT CY OV S
Z
NP
NMI servicing state
0
No NMI interrupt servicing
1
NMI interrupt currently servicing
5.2.4 Noise eliminator of NMI pin
NMI pin noise is eliminated by the noise eliminator with analog delay. Therefore, a signal input to the NMI pin is
not detected as an edge, unless it maintains its input level for a certain period. The edge is detected after a certain
period has elapsed.
NMI pin is used for canceling the software stop mode. In the software stop mode, noise elimination does not use
system clock for noise elimination because the internal system clock is stopped.
Содержание MPD703030A
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