Intel user manual 3.11.38.2System, 46ECB-865User’s Manual

User’s Manual

3.11.38.2System

CLK	Clock provides timing for all transactions on PCI and is an input to every PCI device.
	All other PCI signals, except RST#, INTA#, INTB#, INTC#, and INTD#, are sampled
	on the rising edge of CLK and all other timing parameters are defined with respect to
	this edge. PCI operates up to 33 MHz or 66 MHz and, in general, the minimum
	frequency is DC (0 Hz).
RST#	Reset is used to bring PCI-specific registers, sequencers, and signals to a consistent
	state. What effect RST# has on a device beyond the PCI sequencer is beyond the
	scope of this specification, except for reset states of required PCI configuration
	registers. Anytime RST# is asserted, all PCI output signals must be driven to their
	benign state. In general, this means they must be asynchronously tri-stated. SERR#
	(open drain) is floated. REQ# and GNT# must both be tri-stated (they cannot be
	driven low or high during reset). To prevent AD, C/BE#, and PAR signals from
	floating during reset, the central resource may drive these lines during reset (bus
	parking) but only to a logic low level–they may not be driven high. RST# may be
	asynchronous to CLK when asserted or deasserted. Although asynchronous,
	deassertion is guaranteed to be a clean, bounce-free edge. Except for configuration
	accesses, only devices that are required to boot the system will respond after reset.

46ECB-865 User’s Manual