Motorola MPC8260 - Manual (Page 222)

7-8 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA
Part III. The Hardware Interface
7.2.4.1 Transfer Type (TT[0Ð4])
The transfer type signals (TT[0Ð4]) consist of Þve input/output signals on the MPC8260.
For a complete description of TT[0Ð4] signals and transfer type encoding, see
Section 8.4.3.1, ÒTransfer Type Signal (TT[0Ð4]) Encoding.Ó
7.2.4.1.1 Transfer Type (TT[0Ð4])ÑOutput
Following are the state meaning and timing comments for the TT[0Ð4] output signals on
the MPC8260.
State Meaning Asserted/NegatedÑSpeciÞes the type of transfer in progress.
Timing Comments Assertion/NegationÑSame as A[0Ð31].
High ImpedanceÑSame as A[0Ð31].
7.2.4.1.2 Transfer Type (TT[0Ð4])ÑInput
Following are the state meaning and timing comments for the TT[0Ð4] input signals on the
MPC8260.
State Meaning Asserted/NegatedÑSpeciÞes the type of transfer in progress for
snooping by the MPC8260
Timing Comments Assertion/NegationÑSame as A[0Ð31].
7.2.4.2 Transfer Size (TSIZ[0Ð3])
The transfer size (TSIZ[0Ð3]) signals consist of four input/output signals on the MPC8260,
following are the state meaning and timing comments for the TSIZ[0Ð3] signals on the
MPC8260.
State Meaning Asserted/NegatedÑSpeciÞes the data transfer size for the
transaction (see Section 8.4.3.3, ÒTBST and TSIZ[0Ð3] Signals and
Size of TransferÓ). During graphics transfer operations, these signals
form part of the Resource ID (see TBST).
Timing Comments Assertion/NegationÑSame as A[0Ð31].
High ImpedanceÑSame as A[0Ð31].
7.2.4.3 Transfer Burst (TBST)
The transfer burst (TBST) signal is an input/output signal on the MPC8260. Following are
the state meaning and timing comments for the TBST output/input signal.
State Meaning AssertedÑIndicates that a burst transfer is in progress (see
Section 8.4.3.3, ÒTBST and TSIZ[0Ð3] Signals and Size of
TransferÓ). During graphics transfer operations, this signal forms
part of the Resource ID Þeld from the EAR as follows:
TBST || TSIZ[0Ð3] = EAR[28Ð31]. (See TBST.)
NegatedÑIndicates that a burst transfer is not in progress.
Timing Comments Assertion/NegationÑSame as A[0Р31].