The Cortex-M4 Processor
ARM DUI 0553A
Copyright © 2010 ARM. All rights reserved.
2-31
ID121610
Non-Confidential
2.4.3
Fault status registers and fault address registers
The fault status registers indicate the cause of a fault. For BusFaults and MemManage faults,
the fault address register indicates the address accessed by the operation that caused the fault,
as shown in
2.4.4
Lockup
The processor enters a lockup state if a fault occurs when executing the NMI or HardFault
handlers. When the processor is in lockup state it does not execute any instructions. The
processor remains in lockup state until either:
•
it is reset
•
an NMI occurs
•
it is halted by a debugger.
Note
If lockup state occurs from the NMI handler a subsequent NMI does not cause the processor to
leave lockup state.
Table 2-19 Fault status and fault address registers
Handler
Status register
name
Address register
name
Register description
HardFault
HFSR
-
MemManage
MMFSR
MMFAR
MemManage Fault Status Register
MemManage Fault Address Register
BusFault
BFSR
BFAR
UsageFault
UFSR
-