AMD-K6-2E Datasheet, PDF (155/332 Pages) Advanced Micro Devices – AMD-K6™-2E Embedded Processor

22529B/0—January 2000
Preliminary Information
AMD-K6™-2E Processor Data Sheet
Pipeline Data
Transition
sampled asserted). If the last BRDY# is not sampled asserted,
the processor enters the Pipeline Data state.
If the processor samples the last BRDY# asserted in this state, it
determines if a bus transition is required between the current
bus cycle and the pipelined bus cycle. A bus transition is
required when the data bus direction changes between bus
cycles, such as a memory write cycle followed by a memory read
cycle. If a bus transition is required, the processor enters the
Transition state for one clock to prevent data bus contention. If
a bus transition is not required, the processor enters the Data
state.
The processor does not transition to the Data-NA# Requested
state from the Pipeline Address state because the processor
does not begin sampling NA# until it has exited the Pipeline
Address state.
Two bus cycles are executing concurrently in this state. The
processor cannot issue any additional bus cycles until the
current bus cycle is completed. The processor drives the data
bus during write cycles or expects data to be returned during
read cycles for the current bus cycle until the last BRDY# of the
current bus cycle is sampled asserted.
If the processor samples the last BRDY# asserted in this state, it
determines if a bus transition is required between the current
bus cycle and the pipelined bus cycle. If the bus transition is
required, the processor enters the Transition state for one clock
to prevent data bus contention. If a bus transition is not
required, the processor enters the Data state (NA# was not
sampled asserted) or the Data-NA# Requested state (NA# was
sampled asserted).
The processor enters the Transition state for one clock during
data bus transitions and enters the Data state on the next clock
edge if NA# is not sampled asserted. The sole purpose of this
state is to avoid bus contention caused by bus transitions during
pipeline operation.
Chapter 6
Bus Cycles
137