LM3S101 Datasheet, PDF (73/445 Pages) List of Unclassifed Manufacturers – Microcontroller

Stellaris^® LM3S101 Microcontroller
2.6.3
2.6.4
2.7
2.7.1
though the stack push for the handler failed. The fault handler operates but the stack contents are
corrupted.
Note: Only Reset and NMI can preempt the fixed priority hard fault. A hard fault can preempt any
exception other than Reset, NMI, or another hard fault.
Fault Status Registers and Fault Address Registers
The fault status registers indicate the cause of a fault. For bus faults and memory management
faults, the fault address register indicates the address accessed by the operation that caused the
fault, as shown in Table 2-12 on page 73.
Table 2-12. Fault Status and Fault Address Registers
Handler
Status Register Name
Hard fault
Hard Fault Status (HFAULTSTAT)
Memory management Memory Management Fault Status
fault
(MFAULTSTAT)
Bus fault
Bus Fault Status (BFAULTSTAT)
Usage fault
Usage Fault Status (UFAULTSTAT)
Address Register Name
Register Description
-
page 118
Memory Management Fault page 113
Address (MMADDR)
page 119
Bus Fault Address
(FAULTADDR)
page 113
page 120
-
page 113
Lockup
The processor enters a lockup state if a hard fault occurs when executing the NMI or hard fault
handlers. When the processor is in the lockup state, it does not execute any instructions. The
processor remains in lockup state until it is reset, an NMI occurs, or it is halted by a debugger.
Note: If the lockup state occurs from the NMI handler, a subsequent NMI does not cause the
processor to leave the lockup state.
Power Management
The Cortex-M3 processor sleep modes reduce power consumption:
■ Sleep mode stops the processor clock.
■ Deep-sleep mode stops the system clock and switches off the PLL and Flash memory.
The SLEEPDEEP bit of the System Control (SYSCTRL) register selects which sleep mode is used
(see page 102). For more information about the behavior of the sleep modes, see “System
Control” on page 140.
This section describes the mechanisms for entering sleep mode and the conditions for waking up
from sleep mode, both of which apply to Sleep mode and Deep-sleep mode.
Entering Sleep Modes
This section describes the mechanisms software can use to put the processor into one of the sleep
modes.
The system can generate spurious wake-up events, for example a debug operation wakes up the
processor. Therefore, software must be able to put the processor back into sleep mode after such
an event. A program might have an idle loop to put the processor back to sleep mode.
July 14, 2014
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