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M0A21/M0A23 Series
May 06, 2022
Page
119
of 746
Rev 1.02
M0
A21
/M
0
A
2
3
SE
RIES
TEC
H
NICAL
RE
FEREN
C
E
M
ANUAL
System Reset Status Register (SYS_RSTSTS)
This register provides specific information for software to identify this chip’s reset source from last
operation.
Register
Offset
R/W
Description
Reset Value
SYS_RSTSTS
0x04
R/W
System Reset Status Register
0x0000_0043
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
CPULKRF
7
6
5
4
3
2
1
0
CPURF
Reserved
SYSRF
BODRF
LVRF
WDTRF
PINRF
PORF
Bits Description
[31:9]
Reserved
Reserved.
[8]
CPULKRF
CPU Lockup Reset Flag
0 = No reset from CPU lockup happened.
1 = The Cortex
®
-M0 lockup happened and chip is reset.
Note:
Write 1 to clear this bit to 0.
Note 2:
When CPU lockup happened under ICE is connected, This flag will set to 1 but chip will not reset.
[7]
CPURF
CPU Reset Flag
The CPU reset flag is set by hardware if software writes CPURST (SYS_IPRST0[1]) 1 to reset Cortex
®
- M0
Core and Flash Memory Controller (FMC).
0 = No reset from CPU.
1 = The Cortex
®
-M0 Core and FMC are reset by software setting CPURST to 1.
Note:
Write to clear this bit to 0.
[6]
Reserved
Reserved.
[5]
SYSRF
System Reset Flag
The system reset flag is set by t
he “Reset Signal” from the Cortex
®
-M0 Core to indicate the previous reset
source.
0 = No reset from Cortex
®
-M0.
1 = The Cortex
®
- M0 had issued the reset signal to reset the system by writing 1 to the bit
SYSRESETREQ(AIRCR[2], Application Interrupt and Reset Control Register, address = 0xE000ED0C) in
system control registers of Cortex
®
-M0 core.
Note:
Write 1 to clear this bit to 0.