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38 AMD Geode™ LX Processors Data Book
Signal Definitions
33234H
RESET# Y30 I 0-1 Mb/s 3.3 PCI Reset. RESET# aborts all operations in
progress and places the AMD Geode LX proces-
sor into a reset state. RESET# forces the CPU
and peripheral functions to begin executing at a
known state. All data in the on-chip cache is
invalidated upon a reset.
RESET# is an asynchronous input, but must
meet specified setup and hold times to guarantee
recognition at a particular clock edge. This input
is typically generated during the power-on-reset
(POR) sequence.
STOP# AJ25 I/O 33-66 Mb/s 3.3 Target Stop. STOP# is asserted to indicate that
the current target is requesting the master to stop
the current transaction. This signal is used with
DEVSEL# to indicate retry, disconnect, or target
abort. If STOP# is sampled active while a master,
FRAME# is de-asserted and the cycle is stopped
within three SYSREFs. STOP# can be asserted
when the PCI write buffers are full or a previously
buffered cycle has not completed.
FRAME# AL28 I/O 33-66 Mb/s 3.3 Frame. FRAME# is driven by the current master
to indicate the beginning and duration of an
access. FRAME# is asserted to indicate a bus
transaction is beginning. While FRAME# is
asserted, data transfers continue. When
FRAME# is de-asserted, the transaction is in the
final data phase.
IRDY# AH25 I/O 33-66 Mb/s 3.3 Initiator Ready. IRDY# is asserted to indicate
that the bus master is able to complete the cur-
rent data phase of the transaction. IRDY# is used
in conjunction with TRDY#. A data phase is com-
pleted on any SYSREF in which both IRDY# and
TRDY# are sampled asserted. During a write,
IRDY# indicates valid data is present on
AD[31:0]. During a read, it indicates the master is
prepared to accept data. Wait cycles are inserted
until both IRDY# and TRDY# are asserted
together.
TRDY# AK26 I/O 33-66 Mb/s 3.3 Target Ready. TRDY# is asserted to indicate that
the target agent is able to complete the current
data phase of the transaction. TRDY# is used in
conjunction with IRDY#. A data phase is com-
plete on any SYSREF in which both TRDY# and
IRDY# are sampled asserted. During a read,
TRDY# indicates that valid data is present on
AD[31:0]. During a write, it indicates the target is
prepared to accept data. Wait cycles are inserted
until both IRDY# and TRDY# are asserted
together.
3.4.5 PCI Interface Signals (Continued)
Signal Name Ball No. Type f V Description