Intel 31154 manual Pull-Up/Pull-Down Terminations Sheet 5 of, Signal, Comments, resistor default

Models: 31154

1 72
Download 72 pages 37.2 Kb
Page 23
Image 23
Pull-Up/Pull-Down Terminations (Sheet 5 of 9)

 

 

 

Terminations

Table 5.

Pull-Up/Pull-Down Terminations (Sheet 5 of 9)

 

 

 

 

Signal

 

Pull-Up/Pull-Down or Termination (See Note 1)

Comments

 

 

 

 

 

 

For Hot Swap:

 

 

 

• Depending on Primary PCI Bus frequency

 

 

 

00 = PCI Mode, 33 or 66 MHz (default)

Only valid when HS_SM = 1.

 

 

 

HS_FREQ[1:0]

 

01 = PCI-X 66 MHz

0 = Tie low to GND.

 

 

 

10 = PCI-X 100 MHz

1 = Pull high to 3.3 V through external 8.2 K

 

 

 

 

11 = PCI-X 133 MHz

resistor.

 

 

 

 

 

When not using Hot Swap:

 

 

 

• Tie low to GND.

 

 

 

 

Hardware Straps (sampled at the edge of P_RST#)

 

 

 

 

 

 

 

To disable internal secondary arbiter:

NOTE: S_ARB_LOCK has an effect only when

 

 

• Pull up to 3.3 V through an external 8.2 K

the internal arbiter is enabled.

 

 

resistor.

 

 

 

• S_GNT0# becomes the secondary PCI bus

 

 

 

request output of the 31154, and S_REQ0#

 

 

 

becomes the secondary PCI bus grant input of

 

 

 

the 31154.

 

 

 

To enable internal secondary arbiter:

 

S_ARB_DISABLE/

• Pull down to GND through an external 220

 

S_ARB_LOCK

 

resistor (default).

 

 

 

S_ARB_LOCK (after trailing edge of P_RST#):

 

 

 

• Sampled as 1b, the internal secondary bus

 

 

 

arbiter of the 31154 locks and provides the

 

 

 

grant only to itself.

 

 

 

• When internal arbiter is used and 1b is

 

 

 

sampled after the trailing edge of P_RST#, the

 

 

 

internal secondary bus arbiter of the 31154

 

 

 

locks and provide grant only to itself.

 

 

 

 

 

 

 

To limit secondary bus frequency to maximum of

 

 

 

100 MHz:

 

 

 

• Pull high to 3.3 V through an external 8.2 K

 

S_MAX100

 

resistor.

 

 

 

Otherwise:

 

 

 

• Pull low to GND through an external 330

 

 

 

resistor (default).

 

 

 

 

 

S_TRISTATE

 

GND during normal operation

 

 

 

 

 

NOTES:

1.The recommended value for pull-up resistors for PCI applications is 5.6 K(note that the minimum value for PCI 3.3 V signaling RMIN = 2.42 K, RTYP = 8.2 K, 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 K. For PCI-X, the minimum pull-up resistor value is 5 K, 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 (5 V) or

0 (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.

Intel® 31154 133 MHz PCI Bridge Design Guide Design Guide

23

Page 23
Image 23
Intel manual Pull-Up/Pull-Down Terminations Sheet 5 of, Intel 31154 133 MHz PCI Bridge Design Guide Design Guide, Signal