Functional Peripherals Registers
150
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
Cortex-M4F Peripherals
Table 2-69. CFSR Register Field Descriptions (continued)
Bit
Field
Type
Reset
Description
13
LSPERR
R/W
0h
Indicates if bus fault occurred during FP lazy state preservation.
12
STKERR
R/W
0h
Stacking from exception has caused one or more bus faults. The SP
is still adjusted and the values in the context area on the stack might
be incorrect. The BFAR is not written.
11
UNSTKERR
R/W
0h
Unstack from exception return has caused one or more bus faults.
This is chained to the handler, so that the original return stack is still
present. SP is not adjusted from failing return and new save is not
performed. The BFAR is not written.
10
IMPRECISERR
R/W
0h
Imprecise data bus error. It is a BusFault, but the Return PC is not
related to the causing instruction. This is not a synchronous fault.
So, if detected when the priority of the current activation is higher
than the Bus Fault, it only pends. Bus fault activates when returning
to a lower priority activation. If a precise fault occurs before returning
to a lower priority exception, the handler detects both
IMPRECISERR set and one of the precise fault status bits set at the
same time. The BFAR is not written.
9
PRECISERR
R/W
0h
Precise data bus error return.
8
IBUSERR
R/W
0h
Instruction bus error flag. The IBUSERR flag is set by a prefetch
error. The fault stops on the instruction, so if the error occurs under a
branch shadow, no fault occurs. The BFAR is not written.
7
MMARVALID
R/W
0h
Memory Manage Address Register (MMAR) address valid flag. A
later-arriving fault, such as a bus fault, can clear a memory manage
fault.. If a MemManage fault occurs that is escalated to a Hard Fault
because of priority, the Hard Fault handler must clear this bit. This
prevents problems on return to a stacked active MemManage
handler whose MMAR value has been overwritten.
6
RESERVED
R/W
0h
5
MLSPERR
R/W
0h
Indicates if MemManage fault occurred during FP lazy state
preservation.
4
MSTKERR
R/W
0h
Stacking from exception has caused one or more access violations.
The SP is still adjusted and the values in the context area on the
stack might be incorrect. The MMAR is not written.
3
MUNSTKERR
R/W
0h
Unstack from exception return has caused one or more access
violations. This is chained to the handler, so that the original return
stack is still present. SP is not adjusted from failing return and new
save is not performed. The MMAR is not written.
2
RESERVED
R/W
0h
1
DACCVIOL
R/W
0h
Data access violation flag. Attempting to load or store at a location
that does not permit the operation sets the DACCVIOL flag. The
return PC points to the faulting instruction. This error loads MMAR
with the address of the attempted access.
0
IACCVIOL
R/W
0h
Instruction access violation flag. Attempting to fetch an instruction
from a location that does not permit execution sets the IACCVIOL
flag. This occurs on any access to an XN region, even when the
MPU is disabled or not present. The return PC points to the faulting
instruction. The MMAR is not written.