IBM powerpc 750gx Manual Do Utilizador
User’s Manual
IBM PowerPC 750GX and 750GL RISC Microprocessor
gx_07.fm.(1.2)
March 27, 2006
March 27, 2006
Signal Descriptions
Page 263 of 377
7.2.5.2 Address Retry (ARTRY)
The address retry (ARTRY) signal is both an input and output signal on the 750GX.
Address Retry (ARTRY)—Output
State
Asserted
The 750GX as snooper indicates that the 750GX requires the snooped trans-
action to be rerun. The 750GX might require a snooped transaction to rerun
to perform a snoop copyback first, because it is currently performing a cache
reload for that line (pipeline collision on bus), or because it was unable to
service the snooped address at that time.
action to be rerun. The 750GX might require a snooped transaction to rerun
to perform a snoop copyback first, because it is currently performing a cache
reload for that line (pipeline collision on bus), or because it was unable to
service the snooped address at that time.
Negated/
High
Impedance
High
Impedance
Indicates that the 750GX does not need the snooped address tenure to be
retried.
retried.
Timing
Assertion
Driven and asserted the second cycle following the assertion of TS if a retry
is required. Remains asserted until the cycle following the assertion of
AACK.
is required. Remains asserted until the cycle following the assertion of
AACK.
Negation
Occurs the second bus cycle after the assertion of AACK. Since this signal
might be simultaneously driven by multiple devices, it negates in a unique
fashion. First the buffer goes to high impedance for a minimum of one-half
processor cycle (dependent on the clock mode), and then it is driven negated
for one-half bus cycle before returning to high impedance. This special
method of negation can be disabled by setting precharge disable in
HID0[PAR].
might be simultaneously driven by multiple devices, it negates in a unique
fashion. First the buffer goes to high impedance for a minimum of one-half
processor cycle (dependent on the clock mode), and then it is driven negated
for one-half bus cycle before returning to high impedance. This special
method of negation can be disabled by setting precharge disable in
HID0[PAR].