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Terminology
23-2
MPC801 USER’S MANUAL
MOTOROLA
23
burst length
length of four has four data pieces (four beats) associated with it.
—The number of data associated with a burst cycle. For example, a burst
bus park
cycle. This allows the same master to make the next transfer without having to
rearbitrate for the bus.
—Keeps the bus granted to a bus master although it has completed the bus
C
CAS
—Column address strobe.
copyback
or a transfer of bus control to an external master. At the time of forced update or
relinquishment of the bus, all changes to the cache are written to external memory. Until
that time, cache and external memory are not coherent.
—Updates to external memory are delayed until forced by the user program
critical-data first
organized where the word or data needed first is the first one to transfer within the
burst-data block. The order of transferring can be sequential and usually wraps back to
the word (or data) zero. For example, 1
2
data 1 as the critical data.
—This feature allows the data transferred during the burst cycle to be
3
0 for a sequence of four data with
D
datastream
—A sequence of information to be processed by the core.
DEC
—Decrementer.
E
EBI
—External bus interface.
execution serialization
currently in progress complete execution (all internal pipeline stages and instruction
buffers have emptied and all outstanding memory transactions are completed).
—Instruction issue is halted until all instructions that are
F
fetch serialization
processor have completed execution (all issued instructions as well as the prefetched
instructions waiting to be issued). The machine after fetch serialization is said to be
completely synchronized.
—Instruction fetch is halted until all instructions currently in the
fixed transaction
bus cycle into a single event.
—A bus transaction that combines the address and data phase of the