Intel 31154 manual Pull-Up/Pull-Down Terminations Sheet 8, RSTV0, RSRV1/CRSTEN, SM66EN, Spcixcap

Terminations
Table 5.	Pull-Up/Pull-Down Terminations (Sheet 8 of 9)
Signal		Pull-Up/Pull-Down or Termination (See Note 1)	Comments
RSTV0		Tie to GND through a 0 Ω external resistor.
RSRV1/CRSTEN		Tie to GND through a 0 Ω external resistor.
		S_M66EN is meaningful only when S_PCIXCAP is
		connected to GND (that is, when the secondary
		PCI bus is in legacy PCI mode).
		For designs without secondary PCI slot:
		• When the secondary PCI devices (and
		loading) support 66 MHz PCI bus, pull up to
		3.3 V through an 8.2 KΩ series resistor.
S_M66EN		• When the secondary PCI devices (and	Refer to PCI-X Addendum to the PCI Local Bus
		loading) do not supports 66 MHz PCI bus,	Specification, Revision 1.0b, Table 6-1.
		GND this pin.
		For designs with secondary PCI slot:
		• When the on-board PCI device does not
		support 66 MHz PCI bus, GND this pin.
		• When the on-board PCI device does support
		66 MHz PCI bus, connect this pin to M66EN
		(pin 49B) of the PCI connector.
		For designs without secondary PCI slot:
		• When there is at least one legacy PCI device
		on the secondary PCI bus, tie this pin directly
		to GND.
		• When there is at least one PCI-X device that
		supports maximum PCI-X of only 66 MHz on
		the secondary PCI bus, pull down to GND
		through a 10 KΩ series resistor.
		• When all secondary PCI-X devices (and the
S_PCIXCAP		bus loading) support PCI-X 133 MHz, leave	Refer to PCI-X Addendum to the PCI Local Bus
		this pin unconnected (except for decoupling	Specification, Revision 1.0b, Table 6-1.
		capacitor).
		For designs with secondary PCI slot:
		• When there is at least one on-board legacy
		PCI device on the secondary PCI bus, tie this
		pin directly to GND.
		• Otherwise, connect this pin to PCIXCAP
		(pin B38) of the PCI connector (assuming that
		the bus loading supports up to PCI-X
		133 MHz)

NOTES:

1.The recommended value for pull-up resistors for PCI applications is 5.6 KΩ (note that the minimum value for PCI 3.3 V signaling RMIN = 2.42 KΩ, RTYP = 8.2 KΩ, as per the PCI Local Bus Specification, Revision 2.3, section 4.3.3).

2.The recommended value for pull-up resistors for PCI-X applications is 8.2 KΩ. For PCI-X, the minimum pull-up resistor value is 5 KΩ, as per the PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0b, section 9.7.

3.For plug-in card implementations, the pull-up must be on the motherboard.

4.Connect PVIO and SVIO pull-up resistors to 5 V or 3.3 V power supply through an external resistor—25 Ω (5 V) or

0 Ω (3.3 V), depending on the signaling level of the primary/secondary PCI bus. Refer to the power-sequencing guidelines in Section 8.2 on page 58.

26 Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide