Motorola MPC8260 - Manual (Page 223)

MOTOROLA Chapter 7. 60x Signals 7-9
Part III. The Hardware Interface
High ImpedanceÑSame as A[0Ð31].
7.2.4.4 Global (GBL)
The global (GBL) signal is an input/output signal on the MPC8260.
7.2.4.4.1 Global (GBL)ÑOutput
Following are the state meaning and timing comments for the GBL output signal.
State Meaning AssertedÑIndicates that the transaction is global and should be
snooped by other devices. GBL reßects the M bit (WIM bits) from
the MMU except during certain transactions.
NegatedÑIndicates that the transaction is not global and should not
be snooped by other devices.
Timing Comments Assertion/NegationÑSame as A[0Ð31].
High ImpedanceÑSame as A[0Ð31].
7.2.4.4.2 Global (GBL)ÑInput
Following are the state meaning and timing comments for the GBL input signal.
State Meaning AssertedÑIndicates that a transaction must be snooped by
MPC8260.
NegatedÑIndicates that a transaction should not be snooped by
MPC8260. (In addition, certain non-global transactions are snooped
for reservation coherency.)
Timing Comments Assertion/NegationÑSame as A[0Ð31].
7.2.4.5 Caching-Inhibited (CI)ÑOutput
The cache inhibit (CI) signal is an output signal on the MPC8260. Following are the state
meaning and timing comments for CI.
State Meaning AssertedÑIndicates that the transaction in progress should not be
cached. CI reßects the I bit (WIM bits) from the MMU except during
certain transactions.
NegatedÑIndicates that the transaction should be cached.
Timing Comments Assertion/NegationÑSame as A[0Ð31].
High ImpedanceÑSame as A[0Ð31].
7.2.4.6 Write-Through (WT)ÑOutput
The write-through (WT) signal is an output signal on the MPC8260. Following are the state
meaning and timing comments for WT.
State Meaning AssertedÑIndicates that the transaction should operate in write-
through mode. WT reßects the W bit (WIM bits) from the MMU
except during certain transactions. WT may be asserted during read
transactions.