FW82801E Intel, FW82801E Datasheet - Page 38

• Manufacturer Part Number: FW82801E
• Description: Communications I/O Controller Hub
• Manufacturer: Intel

Intel
38
Table 11. PCI Interface Signals (Sheet 2 of 3)
®
82801E C-ICH
REQ[3:0]#
FRAME#
/REQ[5]#
/REQ[B]#
/GPIO[1]
TRDY#
STOP#
PERR#
IRDY#
Name
PAR
Type
I/O
I/O
I/O
I/O
I/O
I/O
I
Cycle Frame: The current Initiator drives FRAME# to indicate the beginning and
duration of a PCI transaction. While the initiator asserts FRAME#, data transfers
continue. When the initiator negates FRAME#, the transaction is in the final data
phase. FRAME# is an input to the 82801E C-ICH when the 82801E C-ICH is the
target, and FRAME# is an output from the 82801E C-ICH when the 82801E C-ICH
is the Initiator. FRAME# remains tri-stated by the 82801E C-ICH until driven by an
Initiator.
Initiator Ready: IRDY# indicates the 82801E C-ICH’s ability, as an Initiator, to
complete the current data phase of the transaction. It is used in conjunction with
TRDY#. A data phase is completed on any clock both IRDY# and TRDY# are
sampled asserted. During a write, IRDY# indicates the 82801E C-ICH has valid
data present on AD[31:0]. During a read, it indicates the 82801E C-ICH is prepared
to latch data. IRDY# is an input to the 82801E C-ICH when the 82801E C-ICH is the
Target and an output from the 82801E C-ICH when the 82801E C-ICH is an
Initiator. IRDY# remains tri-stated by the 82801E C-ICH until driven by an Initiator.
Target Ready: TRDY# indicates the 82801E C-ICH’s ability as a Target to complete
the current data phase of the transaction. TRDY# is used in conjunction with
IRDY#. A data phase is completed when both TRDY# and IRDY# are sampled
asserted. During a read, TRDY# indicates that the 82801E C-ICH, as a Target, has
placed valid data on AD[31:0]. During a write, TRDY# indicates the 82801E C-ICH,
as a Target is prepared to latch data. TRDY# is an input to the 82801E C-ICH when
the 82801E C-ICH is the Initiator and an output from the 82801E C-ICH when the
82801E C-ICH is a Target. TRDY# is tri-stated from the leading edge of PCIRST#.
TRDY# remains tri-stated by the 82801E C-ICH until driven by a target.
Stop: STOP# indicates that the 82801E C-ICH, as a Target, is requesting the
Initiator to stop the current transaction. STOP# causes the 82801E C-ICH, as an
Initiator, to stop the current transaction. STOP# is an output when the 82801E
C-ICH is a target and an input when the 82801E C-ICH is an Initiator. STOP# is
tri-stated from the leading edge of PCIRST#. STOP# remains tri-stated until driven
by the 82801E C-ICH.
Calculated/Checked Parity: PAR uses “even” parity calculated on 36 bits,
AD[31:0] plus C/BE[3:0]#. “Even” parity means that the 82801E C-ICH counts the
number of 1s within the 36 bits plus PAR and the sum is always even. The 82801E
C-ICH always calculates PAR on 36 bits, regardless of the valid byte enables. The
82801E C-ICH generates PAR for address and data phases and only guarantees
PAR to be valid one PCI clock after the corresponding address or data phase. The
82801E C-ICH drives and tri-states PAR identically to the AD[31:0] lines except that
the 82801E C-ICH delays PAR by exactly one PCI clock. PAR is an output during
the address phase (delayed one clock) for all 82801E C-ICH initiated transactions.
PAR is an output during the data phase (delayed one clock) when the 82801E
C-ICH is the Initiator of a PCI write transaction, and when it is the target of a read
transaction. 82801E C-ICH checks parity when it is the target of a PCI write
transaction. If a parity error is detected, the 82801E C-ICH sets the appropriate
internal status bits, and has the option to generate an NMI# or SMI#.
Parity Error: An external PCI device drives PERR# when it receives data that has
a parity error. The 82801E C-ICH drives PERR# when it detects a parity error. The
ICH can either generate an NMI# or SMI# upon detecting a parity error (either
detected internally or reported via the PERR# signal).
PCI Requests: The 82801E C-ICH supports up to five masters on the PCI bus.
REQ[5]# is muxed with PC/PCI REQ[B]# (must choose one or the other, but not
both). If not used for PCI or PC/PCI, REQ[5]#/REQ[B]# can instead be used as
GPIO[1].
NOTE: REQ[0]# is programmable to have improved arbitration latency for
supporting PCI-based 1394 controllers.
Description
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