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Signal Descriptions
Chapter 5
AMD-K6-2E+ Embedded Processor Data Sheet
23542A/0—September 2000
Preliminary Information
5.4
ADS# (Address Strobe)
Pin Attribute
Output
Summary
The assertion of ADS# indicates the beginning of a new bus
cycle. The address bus and all cycle definition signals
corresponding to this bus cycle are driven valid off the same
clock edge as ADS#.
Driven and Floated
ADS# is asserted for one clock at the beginning of each bus
cycle. For non-pipelined cycles, ADS# can be asserted as early
as the clock edge after the clock edge on which the last
expected BRDY# of the cycle is sampled asserted, resulting in a
single idle state between cycles. For pipelined cycles if the
processor is prepared to start a new cycle, ADS# can be asserted
as early as one clock edge after NA# is sampled asserted.
If AHOLD is sampled asserted, ADS# is only driven in order to
perform a writeback cycle due to an inquire cycle that hits a
modified cache line.
The processor floats ADS# off the clock edge that BOFF# is
sampled asserted and off the clock edge that the processor
asserts HLDA in recognition of HOLD.
5.5
ADSC# (Address Strobe Copy)
Pin Attribute
Output
Summary
ADSC# has the identical function and timing as ADS#. In the
event ADS# becomes too heavily loaded due to a large fanout in
a system, ADSC# can be used to split the load across two
outputs, which can improve system timing.