AMD-K6 Datasheet, PDF (117/346 Pages) Advanced Micro Devices – AMD-K6 Processor

20695H/0—March 1998
Preliminary Information
AMD-K6^® Processor Data Sheet
5.25
Summary
Driven
5.26
Summary
Sampled
Chapter 5
HLDA (Hold Acknowledge)
Output
When HOLD is sampled asserted, the processor completes the
current bus cycles, floats the processor bus, and asserts HLDA
in an acknowledgment that these events have been completed.
The processor does not assert HLDA until the completion of a
locked sequence of cycles. While HLDA is asserted, another bus
master can drive cycles on the bus, including inquire cycles to
the processor. The following signals are floated when HLDA is
asserted: 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 #.
The processor ensures that HLDA does not glitch.
HLDA is always driven except in Tri-State Test mode. If a
processor cycle is in progress while HOLD is sampled asserted,
HLDA is asserted one clock edge after the last BRDY # of the
cycle is sampled asserted. If the bus is idle, HLDA is asserted
one clock edge after HOLD is sampled asserted. HLDA is
negated one clock edge after the clock edge on which HOLD is
sampled negated.
The assertion of HLDA is independent of the sampled state of
BOFF #.
The processor floats the bus every clock in which HLDA is
asserted.
HOLD (Bus Hold Request)
Input
The system logic can assert HOLD to gain control of the
processor’s bus. When HOLD is sampled asserted, the processor
completes the current bus cycles, floats the processor bus, and
asserts HLDA in an acknowledgment that these events have
been completed.
The processor samples HOLD on every clock edge. If a
processor cycle is in progress while HOLD is sampled asserted,
HLDA is asserted one clock edge after the last BRDY # of the
cycle is sampled asserted. If the bus is idle, HLDA is asserted
one clock edge after HOLD is sampled asserted. HOLD is
recognized while INIT and RESET are sampled asserted.
Signal Descriptions
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