Intel 440GX manual Dual Processor Systems, Single Processor Systems-Single-End Termination SET

Motherboard Layout and Routing Guidelines

2.3.4Dual Processor Systems

2.3.4.1Dual Processor Network Topology and Conditions

Figure 2-9. Recommended Topology for Dual Processor Design

Slot 1

Intel® 440GX AGPset

	L3
L4		L5

Slot 1

2.3.4.2Dual Processor Recommended Trace Lengths

The recommended trace lengths for dual processor designs are summarized in Table 2-2. Intel’s simulations have shown that it is desirable to control the amount of imbalance in the network to meet ringback specifications at the Intel® Pentium® II processor when the Intel® 440GX AGPset drives. This control is reflected in the recommendations of Table 2-2.

Table 2-2. Recommended Trace Lengths for Dual Processor Designs2

Trace	Minimum Length	Maximum Length
L3	0.50”	1.50”
L41	1.50”	4.00”
L52	L4 - 1.00”, but L4+L5 must be at least 4.00”	L4 + 1.00”, but not greater than 5.00”

NOTES:

1.L4 & L5 are interchangeable

2.It is possible to find working solutions outside the recommendations of Table 2-2, as the solution space plot show. Intel strongly recommends that any traces that fall outside the recommended lengths be simulated to ensure they meeting timing and signal quality specs.

2.3.5Single Processor Systems—Single-End Termination (SET)

2.3.5.1Set Network Topology and Conditions

Removal of the termination resistors from the system board can reduce system cost, at the expense of increased ringing and reduced solution space. Intel has simulated this topology, known as single end termination (SET), and found that it can work. However, the topology has some limitations which are discussed below.

2-8 Intel®440GX AGPset Design Guide