Cortex-M3 Processor (Reference Material)
UG0331 User Guide Revision 15.0
26
Fault Mask Register
The FAULTMASK register prevents activation of all exceptions except for Non-Maskable Interrupt (NMI).
See the register summary in
page 21 for its attributes.
The following table lists the big assignments for MSR or MRS access.
The processor clears the FAULTMASK bit to 0 on exit from any exception handler except the NMI
handler.
Base Priority Mask Register
The BASEPRI register defines the minimum priority for exception processing. When BASEPRI is set to a
nonzero value, it prevents the activation of all exceptions with the same or lower priority level as the
BASEPRI value. See the register summary in
page 21 for its attributes.
Figure 9 •
Base Priority Mask Register
The following table lists the big assignments for MSR or MRS access.
Figure 8 •
Fault Mask Register
Table 14 •
FAULT Register Bit Assignments
Bits
Name
Function
[31:1]
-
Reserved
[0]
FAULTMASK 0: no effect
1: prevents the activation of all exceptions except for NMI.
Table 15 •
BASEPRI Register Bit Assignments
Bits
Name
Function
[31:8]
Reserved
[7:0]
BASEPRI
1
1.
This field is similar to the priority fields in the interrupt priority registers. The device implements only
bits[7:M] of this field, bits [M-1:0] read as zero and ignore writes. See
page 99 for more information. Remember that higher priority field values correspond to lower exception
priorities.
Priority mask bits:
0x00: no effect
Nonzero: defines the base priority for exception processing.
The processor does not process any exception with a priority value
greater than or equal to BASEPRI.
31
1 0
Reserved
FAULTMASK
Reserved
BASEPRI
31
8 7
0