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7 .2.4.5 Write-Through (WT)-Output
The write-through (WT) signal is an output signal on the MPC750. Following are the state
meaning and timing comments for the WT signal.
State Meaning
Asserted-Indicates that a single-beat write transaction is write-
through, reflecting the value of the W bit for the block or page that
contains the address of the current transaction. Assertion during a
read operation indicates instruction fetching.
Negated-Indicates that a write transaction is not write-through;
during a read operation negation indicates a data load.
Timing Comments AssertionlNegation-The same asA[0-31].
High Impedance-The same as A[0-31].
7.2.4.6 Global (GBl)
The global (GBL) signal is an input/output signal on the MPC750.
7.2.4.6.1 Global (GBL)-Output
Following are the state meaning and timing comments for the GBL output signal.
State Meaning
Asserted-Indicates that a transaction is global, reflecting the setting
of the M bit for the block or page that contains the address of the
current transaction (except in the case of copy-back operations and
instruction fetches, which are nonglobal.)
Negated-Indicates that a transaction is not global.
Timing Comments AssertionlNegation-The same asA[0-31].
High Impedance-The same as A[0-31].
7.2.4.6.2 Global (GBL)-Input
Following are the state meaning and timing comments for the GBL input signal.
State Meaning
Asserted-Indicates that a transaction must be snooped by the
MPC750.
Negated-Indicates that a transaction is not snooped by the
MPC750.
Timing Comments AssertionlNegation-The same as A[0-31].
7.2.5 Address Transfer Termination Signals
The address transfer termination signals are used to indicate either that the address phase
of the transaction has completed successfully or must be repeated, and when it should be
terminated. For detailed information about how these signals interact, see Section 8.3.3,
"Address Transfer Termination."
Chapter 7. Signal Descriptions
7-13
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