Address Transfer Signals; Address Bus (A[0-31]) - IBM PowerPC 750GX User Manual

User's Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor

7.2.3 Address Transfer Signals

The address transfer signals are used to transmit the address and to generate and monitor parity for the
address transfer. For a detailed description of how these signals interact, see Section 8.3.2, Address
Transfer, on page 292.
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.
Address Bus (A[0–31])—Output
State Asserted/
Negated
Timing Assertion/
Negation
High
Impedance
Address Bus (A[0–31])—Input
State Asserted/
Negated
Timing Assertion/
Negation
Signal Descriptions
Page 254 of 377
Represents the physical address (real address in the architecture specifica-
tion) of the data to be transferred. On burst transfers, the address bus
presents the double-word-aligned address containing the critical code/data
that missed the cache on a read operation, or the first double word of the
cache line on a write operation. Note that the address output during burst
operations is not incremented. See Section 8.3.2, Address Transfer, on
page 292.
Occurs on the bus clock cycle after a qualified bus grant (coincides with
assertion of TS). Remains driven/valid for the duration of the address tenure.
Occurs one bus clock cycle following the assertion of AACK; no precharge
action is performed on release.
Represents the physical address of a snoop operation.
Must occur on the same bus clock cycle as the assertion of TS; is sampled by
the 750GX only on this cycle.
gx_07.fm.(1.2)
March 27, 2006