
MOTOROLA
Chapter 9. Core Interface Operation
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9-11
Address Bus Tenure
Figure 9-4. Address Bus Arbitration Showing Bus Parking
9.3.2
Address Transfer
During the address transfer, the physical address and all attributes of the transaction are
transferred from the bus master to slave devices. Snooping logic may monitor the transfer
to enforce cache coherency; see description of bus snooping in Section 9.3.3, “Address
Transfer Termination.”
The signals used in the address transfer include the following signal groups:
Address transfer start signal: Transfer start (core_ts_out)
Address transfer signals: Address bus (core_a_out[0:31]), address parity
(core_ap_out[0:3]), and address parity error (core_ape).
Address transfer attribute signals: Transfer type (core_tt_out[0:4]), transfer code
(core_tc[0:1]), transfer size (core_tsiz[0:2]), transfer burst (core_tbst), cache inhibit
(core_ci), write-through (core_wt), global (core_gbl_out), and cache set element
(core_cse[0:1]).
Figure 9-5 shows that the timing for all of these signals, except core_ts_out and core_ape,
is identical. All of the address transfer and address transfer attribute signals are combined
into the ADDR+ grouping in Figure 9-5. The core_ts_out signal indicates that the core has
begun an address transfer and that the address and transfer attributes are valid (within the
context of a synchronous bus). The core always asserts core_ts_out coincident with
core_abb_out. As an input, core_ts_in need not coincide with the assertion of core_abb_in
need_bus
core_br
core_bg
core_abb_in
core_artry
qual_bg
core_abb_out
Bus Clock
–1
0
1
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