Intel GD82559ER - Manual (Page 14)

GD82559ER — Networking Silicon
8 Datasheet
3.2.2 Interface Control Signals
Symbol Type Name and Function
FRAME# S/T/S
Cycle Frame. The cycle frame signal is driven by the current master
to indicate the beginning and duration of a transaction. FRAME# is
asserted to indicate the start of a transaction and de-asserted during
the final data phase.
IRDY# S/T/S
Initiator Ready. The initiator ready signal indicates the bus master’s
ability to complete the current data phase and is used in conjunction
with the target ready (TRDY#) signal. A data phase is completed on
any clock cycle where both IRDY# and TRDY# are sampled asserted
(low) simultaneously.
TRDY# S/T/S
Target Ready. The target ready signal indicates the selected device’s
ability to complete the current data phase and is used in conjunction
with the initiator ready (IRDY#) signal. A data phase is completed on
any clock cycle where both IRDY# and TRDY# are sampled asserted
(low) simultaneously.
STOP# S/T/S
Stop. The stop signal is driven by the target to indicate to the initiator
that it wishes to stop the current transaction. As a bus slave, STOP# is
driven by the 82559ER to inform the bus master to stop the current
transaction. As a bus master, STOP# is received by the 82559ER to
stop the current transaction.
IDSEL IN
Initialization Device Select. The initialization device select signal is
used by the 82559ER as a chip select during PCI configuration read
and write transactions. This signal is provided by the host in PCI
systems.
DEVSEL# S/T/S
Device Select. The device select signal is asserted by the target once
it has detected its address. As a bus master, the DEVSEL# is an input
signal to the 82559ER indicating whether any device on the bus has
been selected. As a bus slave, the 82559ER asserts DEVSEL# to
indicate that it has decoded its address as the target of the current
transaction.
REQ# T/S
Request. The request signal indicates to the bus arbiter that the
82559ER desires use of the bus. This is a point-to-point signal and
every bus master has its own REQ#.
GNT# IN
Grant. The grant signal is asserted by the bus arbiter and indicates to
the 82559ER that access to the bus has been granted. This is a point-
to-point signal and every master has its own GNT#.
INTA# O/D
Interrupt A. The interrupt A signal is used to request an interrupt by
the 82559ER. This is an active low, level triggered interrupt signal.
SERR# O/D
System Error. The system error signal is used to report address
parity errors. When an error is detected, SERR# is driven low for a
single PCI clock.
PERR# S/T/S
Parity Error. The parity error signal is used to report data parity errors
during all PCI transactions except a Special Cycle. The parity error pin
is asserted two clock cycles after the error was detected by the device
receiving data. The minimum duration of PERR# is one clock for each
data phase where an error is detected. A device cannot report a parity
error until it has claimed the access by asserting DEVSEL# and
completed a data phase.