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M0A21/M0A23 Series
May 06, 2022
Page
173
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
Interrupt Control State Register (ICSR)
Register
Offset
R/W
Description
Reset Value
ICSR
0xD04
R/W
Interrupt Control and State Register
0x0000_0000
31
30
29
28
27
26
25
24
NMIPENDSET
Reserved
PENDSVSET
PENDSVCLR
PENDSTSET
PENDSTCLR
Reserved
23
22
21
20
19
18
17
16
ISRPREEMPT ISRPENDING
Reserved
VECTPENDING
15
14
13
12
11
10
9
8
VECTPENDING
RETTOBASE
Reserved
7
6
5
4
3
2
1
0
Reserved
VECTACTIVE
Bits
Description
[31]
NMIPENDSET
NMI Set-pending Bit
Write Operation:
0 = No effect.
1 = Changes NMI exception state to pending.
Read Operation:
0 = NMI exception is not pending.
1 = NMI exception is pending.
Note:
Because NMI is the highest-priority exception, normally the processor enters the NMI exception
handler as soon as it detects a write of 1 to this bit. Entering the handler then clears this bit to 0. This
means a read of this bit by the NMI exception handler returns 1 only if the NMI signal is reasserted while
the processor is executing that handler.
[30:29]
Reserved
Reserved.
[28]
PENDSVSET
PendSV Set-pending Bit
Write Operation:
0 = No effect.
1 = Changes PendSV exception state to pending.
Read Operation:
0 = PendSV exception is not pending.
1 = PendSV exception is pending.
Note:
Writing 1 to this bit is the only way to set the PendSV exception state to pending.
[27]
PENDSVCLR
PendSV Clear-pending Bit
Write Operation:
0 = No effect.
1 = Removes the pending state from the PendSV exception.
Note:
This is a write only bit. To clear the
PENDSV bit, you must “write 0 to PENDSVSET and write 1
to PENDSVRTC_CAL” at the same time.