Intel GD82559ER manual Interface Control Signals

GD82559ER — Networkin g Silicon

3.2.2Interface Control Signals

Symbol	Type	Name and Function
		Cycle Frame. The cycle frame signal is driven by the current master
FRAME#	S/T/S	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.
		Initiator Ready. The initiator ready signal indicates the bus master’s
		ability to complete the current data phase and is used in conjunction
IRDY#	S/T/S	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.
		Target Ready. The target ready signal indicates the selected device’s
		ability to complete the current data phase and is used in conjunction
TRDY#	S/T/S	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. 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
STOP#	S/T/S	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.
		Initialization Device Select. The initialization device select signal is
IDSEL	IN	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.
		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
DEVSEL#	S/T/S	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.
		Request. The request signal indicates to the bus arbiter that the
REQ#	T/S	82559ER desires use of the bus. This is a point-to-point signal and
		every bus master has its own REQ#.
		Grant. The grant signal is asserted by the bus arbiter and indicates to
GNT#	IN	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.
		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
PERR#	S/T/S	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.

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