Description
Reset
Type
Name
Bit/Field
Invalid State Usage Fault
Description
Value
A usage fault has not been caused by an invalid state.
0
The processor has attempted to execute an instruction that
makes illegal use of the
EPSR
register.
1
When this bit is set, the
PC
value stacked for the exception return points
to the instruction that attempted the illegal use of the
Execution
Program Status Register (EPSR)
register.
This bit is not set if an undefined instruction uses the
EPSR
register.
This bit is cleared by writing a 1 to it.
0
RW1C
INVSTAT
17
Undefined Instruction Usage Fault
Description
Value
A usage fault has not been caused by an undefined instruction.
0
The processor has attempted to execute an undefined
instruction.
1
When this bit is set, the
PC
value stacked for the exception return points
to the undefined instruction.
An undefined instruction is an instruction that the processor cannot
decode.
This bit is cleared by writing a 1 to it.
0
RW1C
UNDEF
16
Bus Fault Address Register Valid
Description
Value
The value in the
Bus Fault Address (FAULTADDR)
register
is not a valid fault address.
0
The
FAULTADDR
register is holding a valid fault address.
1
This bit is set after a bus fault, where the address is known. Other faults
can clear this bit, such as a memory management fault occurring later.
If a bus fault occurs and is escalated to a hard fault because of priority,
the hard fault handler must clear this bit. This action prevents problems
if returning to a stacked active bus fault handler whose
FAULTADDR
register value has been overwritten.
This bit is cleared by writing a 1 to it.
0
RW1C
BFARV
15
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should be
preserved across a read-modify-write operation.
0
RO
reserved
14
Bus Fault on Floating-Point Lazy State Preservation
Description
Value
No bus fault has occurred during floating-point lazy state
preservation.
0
A bus fault has occurred during floating-point lazy state
preservation.
1
This bit is cleared by writing a 1 to it.
0
RW1C
BLSPERR
13
June 18, 2014
186
Texas Instruments-Production Data
Cortex-M4 Peripherals