Motorola MVME166IG/D2 - Manual (Page 58)

Debugger General Information
3-12 MVME166 Single Board Computer Installation Guide
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registers are invalidated. Input and output character queues are cleared.
Onboard devices (timer, serial ports, etc.) are reset, and the first two serial
ports are reconfigured to their default state.
During WARM reset, the 166Bug variables and tables are preserved, as well as
the target state registers and breakpoints.
Reset must be used if the processor ever halts, or if the 166Bug environment is
ever lost (vector table is destroyed, stack corrupted, etc.).
Abort
Abort is invoked by pressing and releasing the ABORT switch on the
MVME166 front panel. Whenever abort is invoked when executing a user
program (running target code), a "snapshot" of the processor state is captured
and stored in the target registers. For this reason, abort is most appropriate
when terminating a user program that is being debugged. Abort should be
used to regain control if the program gets caught in a loop, etc. The target PC,
register contents, etc., help to pinpoint the malfunction.
Pressing and releasing the ABORT switch generates a local board condition
which may interrupt the processor if enabled. The target registers, reflecting
the machine state at the time the ABORT switch was pressed, are displayed on
the screen. Any breakpoints installed in your code are removed and the
breakpoint table remains intact. Control is returned to the debugger.
Break
A "Break" is generated by pressing and releasing the BREAK key on the
terminal keyboard. Break does not generate an interrupt. The only time break
is recognized is when characters are sent or received by the console port.
Break removes any breakpoints in your code and keeps the breakpoint table
intact. Break also takes a snapshot of the machine state if the function was
entered using SYSCALL. This machine state is then accessible to you for
diagnostic purposes.
Many times it may be desirable to terminate a debugger command prior to its
completion; for example, during the display of a large block of memory. Break
allows you to terminate the command.
SYSFAIL* Assertion/Negation
Upon a reset/powerup condition the debugger asserts the VMEbus SYSFAIL*
line (refer to the VMEbus specification). SYSFAIL* stays asserted if any of the
following has occurred: