Datasheet

A-10 MCF5407 User’s Manual
Revision C Debug
0xCF4x_C012 identify the MCF5407, where x identifies the core revision number (0x1 for
the initial device).
A.8 Revision C Debug
A number of enhancements to the original ColdFire debug functions were requested by
customers and third-party tool developers. As a result, an expanded set of debug functions
was implemented in the Version 4 ColdFire and named Revision C, or simply Debug C.
Most of the enhancements are included in the MCF5407 debug module and are primarily
related to improvements in the real-time debug capabilities.
A.8.1 Debug Interrupts and Interrupt Requests
in Emulator Mode
In the Debug B ColdFire implementation of the MCF5307, the response to a user-defined
breakpoint trigger can be configured as one of three possibilities:
• The breakpoint trigger can be displayed on the PSTDDATA bus with no internal
reaction to the trigger. The trigger state information is displayed on PSTDDATA in
all situations.
• The breakpoint trigger can force the processor to halt and allow BDM activities.
• The breakpoint trigger can generate a special debug interrupt to allow real-time
systems to quickly process the interrupt and return to normal system executing as
rapidly as possible.
The occurrence of a debug interrupt exception is treated as a special type of interrupt. It is
considered to be higher in priority than all normal interrupt requests and has special
processor status values to indicate externally that this interrupt occurred.
Additionally, the execution of the debug interrupt service routine is forced to be
interrupt-inhibited by the processor hardware. Optionally, it is capable of mapping all
instruction and data references while in this service routine into a separate address space,
so that an emulator can define the routine dynamically.
Current processor implementations include a state bit, invisible to software, that defines this
emulator mode of operation. Note that the interrupt mask level is not modified during the
processing of a debug interrupt.
In response to customers with real-time embedded systems asking for the ability to service
normal interrupt requests while processing the debug interrupt service routine, this feature
has been incorporated in the Revision C debug. To provide this function and service any
number of normal interrupt requests, including the possibility of nested interrupts, the
processor state signaling emulator mode is now included as part of the exception stack