SCB Registers
160
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Cortex-M4 Peripherals
2.5.11 SYSHNDCTRL Register (Offset = 0xD24) [reset = 0x0]
System Handler Control and State (SYSHNDCTRL)
NOTE:
This register can only be accessed from privileged mode.
The SYSHNDCTRL register enables the system handlers, and indicates the pending status of the usage
fault, bus fault, memory management fault, and SVC exceptions as well as the active status of the system
handlers.
If a system handler is disabled and the corresponding fault occurs, the processor treats the fault as a hard
fault.
This register can be modified to change the pending or active status of system exceptions. An OS kernel
can write to the active bits to perform a context switch that changes the current exception type.
NOTE:
Software that changes the value of an active bit in this register without correct adjustment to
the stacked content can cause the processor to generate a fault exception. Ensure software
that writes to this register retains and subsequently restores the current active status.
If the value of a bit in this register must be modified after enabling the system handlers, a
read-modify-write procedure must be used to ensure that only the required bit is modified.
SYSHNDCTRL is shown in
and described in
.
Return to
Figure 2-23. SYSHNDCTRL Register
31
30
29
28
27
26
25
24
RESERVED
R-0x0
23
22
21
20
19
18
17
16
RESERVED
USAGE
BUS
MEM
R-0x0
R/W-0x0
R/W-0x0
R/W-0x0
15
14
13
12
11
10
9
8
SVC
BUSP
MEMP
USAGEP
TICK
PNDSV
RESERVED
MON
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R-0x0
R/W-0x0
7
6
5
4
3
2
1
0
SVCA
RESERVED
USGA
RESERVED
BUSA
MEMA
R/W-0x0
R-0x0
R/W-0x0
R-0x0
R/W-0x0
R/W-0x0
Table 2-36. SYSHNDCTRL Register Field Descriptions
Bit
Field
Type
Reset
Description
31-19
RESERVED
R
0x0
18
USAGE
R/W
0x0
Usage Fault Enable
17
BUS
R/W
0x0
Bus Fault Enable
16
MEM
R/W
0x0
Memory Management Fault Enable
15
SVC
R/W
0x0
SVC Call Pending
This bit can be modified to change the pending status of the SVC
call exception.
14
BUSP
R/W
0x0
Bus Fault Pending
This bit can be modified to change the pending status of the bus
fault exception.