S5935QF Applied Micro Circuits Corporation, S5935QF Datasheet - Page 113

• Manufacturer Part Number: S5935QF
• Manufacturer: Applied Micro Circuits Corporation

Specifications of S5935QF

• Package Type: PQFP
• Rad Hardened: No
• Lead Free Status / Rohs Status: Not Compliant

S5935 – PCI Product
Targets selected with LOCK# deasserted during the
assertion of FRAME# (clock period 1 of Figure 15),
which encounter the assertion of LOCK# during the
following clock (clock period 2 of Figure 15) are there-
after considered “locked.” A target, once locked,
requires that subsequent accesses to it deassert
LOCK# while FRAME# is asserted. Figure 16 show a
subsequent access to a locked target by the master
which locked it. Because LOCK# is owned by a single
master, only that master is able to deassert it at the
beginning of a transaction (allowing successful access
to the locked target). A locked target can only be
unlocked during the clock period following the last data
transfer of a transaction when the LOCK# signal is
deasserted.
Figure 61. Access to a Locked Target by its Owner
Figure 62. Access Attempt to a Locked Target
AMCC Confidential and Proprietary
PCI CLOCK
FRAME #
LOCK #
AD [31:0]
IRDY#
TRDY#
DEVSEL#
PCI CLOCK
FRAME #
LOCK #
AD [31:0]
IRDY#
TRDY#
DEVSEL#
STOP#
(T)
(T)
(I)
(I)
(I)
(T)
(T)
(T)
(I)
(I)
(I)
TARGET IDENTIFIES
THAT BUS MASTER
IS NOT ITS OWNER
IDENTIFIES
1
1
LOCKED
TARGET
ADDRESS
OWNER
LOCKED
ADDRESS
2
2
DATA
DATA
An unlocked target ignores LOCK# when it observes
that LOCK# is already asserted during the first clock
period of a transaction. This allows other masters to
access other (unlocked) targets. If an access to a
locked target is attempted by a master other than the
one that locked it, the target responds with a retry
request, as shown in Figure 17.
The S5935 responds to and supports bus masters
which lock it as a target. When the S5935 is a bus
master, it never attempts to lock a target, but it honors
a target’s request for retry if that target is locked by
another master.
3
3
DATA
RETRY TERMINATION
CAUSES TARGET
CONDITION
UNLOCKS
TARGET
WHICH
45
45
(I) = DRIVEN BY INITIATOR
(T) = DRIVEN BY TARGET
(I) = DRIVEN BY INITIATOR
(T) = DRIVEN BY TARGET
Revision 1.02 – June 27, 2006
Data Book
DS1527
113