Freescale Semiconductor MPC8260 - Manual (Page 262)

60x Signals
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
7-6 Freescale Semiconductor
bus request if the transfer attributes TT[0–4] indicate that a data tenure is required
for the transaction.
Negated—Has no special meaning during a normal transaction.
Timing Comments Assertion/Negation—Driven and asserted on the cycle after a qualified BG is
accepted by PowerQUICC II; remains asserted for one clock only. Negated for the
remainder of the address tenure. Assertion is coincident with the first clock that
ABB is asserted.
High Impedance—Occurs the cycle following the assertion of AACK (same cycle
as ABB negation).
7.2.2.2 Transfer Start (TS)—Input
Following are the state meaning and timing comments for the TS input signal.
State Meaning Asserted—Indicates that another device has begun a bus transaction and that the
address bus and transfer attribute signals are valid for snooping.
Negated—Has no special meaning.
Timing Comments Assertion/Negation—Must be asserted for one cycle only and then immediately
negated. Assertion may occur at any time during the assertion of ABB.
7.2.3 Address Transfer Signals
In internal only mode the memory controller uses these signals for glueless address transfers to memory
and I/O devices.
The address transfer signals are used to transmit the address.
7.2.3.1 Address Bus (A[0–31])
The address bus (A[0–31]) consists of 32 signals that are both input and output signals.
7.2.3.1.1 Address Bus (A[0–31])—Output
Following are the state meaning and timing comments for the A[0–31] output signals.
State Meaning Content—Specifies the physical address of the bus transaction. For burst or
extended operations, the address is a double-word.
Timing Comments Assertion/Negation—Driven valid on the same cycle that TS is driven/asserted;
remains driven/valid for the duration of the address tenure.
High Impedance— Occurs the cycle following the assertion of AACK; no
precharge action performed on release.
7.2.3.1.2 Address Bus (A[0–31])—Input
Following are the state meaning and timing comments for the A[0–31] input signals.