AMD-K6 Datasheet, PDF (105/346 Pages) Advanced Micro Devices – AMD-K6 Processor

20695H/0—March 1998
Preliminary Information
AMD-K6^® Processor Data Sheet
5.10
Summary
Sampled
BOFF# (Backoff)
Input
If BOFF # is sampled asserted, the processor unconditionally
aborts any cycles in progress and transitions to a bus hold state
by floating the following signals: A[31:3], ADS #, ADSC #, AP,
BE[7:0]#, CACHE #, D[63:0], D/C #, DP[7:0], LOCK #, M/IO #,
PCD, PWT, SCYC, and W/R#. These signals remain floated until
BOFF# is sampled negated. This allows an alternate bus master
or the system to control the bus.
When BOFF# is sampled negated, any processor cycle that was
aborted due to the assertion of BOFF # is restarted from the
beginning of the cycle, regardless of the number of transfers
that were completed. If BOFF # is sampled asserted on the same
clock edge as BRDY# of a bus cycle of any length, then BOFF#
takes precedence over the BRDY #. In this case, the cycle is
aborted and restarted after BOFF # is sampled negated.
BOFF# is sampled on every clock edge. The processor floats its
bus signals off the clock edge on which BOFF # is sampled
asserted. These signals remain floated until the clock edge on
which BOFF# is sampled negated.
BOFF # is recognized while INIT and RESET are sampled
asserted.
Chapter 5
Signal Descriptions
87