Hello All,
  I'm not sure why you would want to re-run a failed bus cycle
but:

"4.2.4.2 RE-RUN OPERATION:  When, during a bus cycle, the
processor receives a bus error signal and the halt pin is being
driver by an external device, the processor enters the re-run
sequence. ...

The processor terminates the bus cycle, then puts the address and
data output lines in the high-impedence state.  The processor
remains "halted", and will not run another bus cycle until the
halt signal is removed by external logic.  Then the processor
will re-run the previous cycle using the same function codes, the
same data (for a write operation), and the same controls.  The
bus error signal should be removed at least one clock cycle
before the halt signal is removed."

The above is from a Motorola publication title "MC68000
16-/32-bit Microprocessor" and dated October, 1985.  It is
labeled as advance info.  Section 5.2.4.2 of the "M68000
8-/16-/32-Bit Microprocessor User's Manual", 8th ed, copyrighted
1990 has essentially the same info.

Happy hacking....



Steven Grunza
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