ISD94100 Series Technical Reference Manual
Sep 9, 2019
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Rev1.09
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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
PMURF
SYSRF
BODRF
LVRF
WDTRF
PINRF
PORF
Bits
Description
[31:9]
Reserved
Reserved. Any values read should be ignored. When writing to this field always write with
reset value.
[8]
CPULKRF
CPU Lockup Reset Flag
0 = No reset from CPU lockup occurred.
1 = The Cortex-M4 lockup occurred and chip is reset.
Note:
Write 1 to clear this bit to 0.
Note:
when ICE is connected, CPU lockup event sets this flag to 1 but will not reset chip.
[7]
CPURF
CPU Reset Flag
The CPU reset flag is set by hardware if software writes CPURST (SYS_IPRST0[1]) 1 to
reset Cortex
®
-M4 Core and Flash Memory Controller (FMC).
0 = No reset from CPU.
1 = The Cortex
®
-M4 Core and FMC are reset by software setting CPURST to 1.
Note:
Write 1 to clear this bit to 0.
[6]
PMURF
PMU Reset Flag
0 = No reset from POR, PINR, WDTR, LVR, BODR, SYSR and CPULKR.
1 = When POR, PINR, WDTR, LVR, BODR, SYSR and CPULKR occurred.
Note:
Write 1 to clear this bit to 0.
[5]
SYSRF
System Reset Flag
The system reset flag is set by the “Reset Signal” from the Cortex
®
-M4 Core to indicate the
previous reset source.
0 = No reset from Cortex
®
-M4.
1 = The Cortex
®
-M4 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
®
-M4 core.
Note:
Write 1 to clear this bit to 0.