Chapter 2. ColdFire Core
2-41
Exception Processing Overview
If a ColdFire processor encounters any type of fault during the exception processing of
another fault, the processor immediately halts execution with the catastrophic fault-on-fault
condition. A reset is required to force the processor to exit this halted state.
Interrupt
Exception
Interrupt exception processing, with interrupt recognition and vector fetching, includes uninitialized
and spurious interrupts as well as those where the requesting device supplies the 8-bit interrupt
vector.
Reset
Exception
Asserting the reset input signal (RSTI) causes a reset exception. Reset has the highest exception
priority; it provides for system initialization and recovery from catastrophic failure. When assertion of
RSTI is recognized, current processing is aborted and cannot be recovered. The reset exception
places the processor in supervisor mode by setting SR[S] and disables tracing by clearing SR[T].
This exception also clears SR[M] and sets the processor’s interrupt priority mask in the SR to the
highest level (level 7). Next, the VBR is initialized to 0x0000_0000. Configuration registers controlling
the operation of all processor-local memories (cache and RAM modules on the MCF5272) are
invalidated, disabling the memories.
Note: Other implementation-specific supervisor registers are also affected. Refer to each of the
modules in this manual for details on these registers.
If the processor is not halted and it has ownership of the bus, it initiates the reset exception by
performing two longword read bus cycles. The longword at address 0 is loaded into the stack pointer
and the longword at address 4 is loaded into the PC. After the initial instruction is fetched from
memory, program execution begins at the address in the PC. If an access error or address error
occurs before the first instruction executes, the processor enters the fault-on-fault halted state.
Table 2-21. MCF5
272
Exceptions (Continued)
Exception
Description
Содержание DigitalDNA ColdFire MCF5272
Страница 1: ...MCF5272UM D Rev 0 02 2001 MCF5272 ColdFire Integrated Microprocessor User s Manual ...
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Страница 90: ...2 42 MCF5272 User s Manual Exception Processing Overview ...
Страница 96: ...3 6 MCF5272 User s Manual MAC Instruction Execution Timings ...
Страница 158: ...5 46 MCF5272 User s Manual Motorola Recommended BDM Pinout ...
Страница 184: ...7 12 MCF5272 User s Manual Interrupt Controller Registers ...
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Страница 414: ...18 6 MCF5272 User s Manual PWM Programming Model ...
Страница 452: ...19 38 MCF5272 User s Manual Power Supply Pins ...
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Страница 492: ...21 10 MCF5272 User s Manual Non IEEE 1149 1 Operation ...
Страница 548: ...INDEX Index 12 MCF5272 User s Manual ...