Intel 440GX manual 10. Recommended 100 MHz System Timing Parameters, Tflight,min, Tflight,max

Motherboard Layout and Routing Guidelines

Notice that the timing equations include an extra term to account for the delay due to routing of the BCLK trace on the processor substrate from the processor edge fingers and the processor core. Adding the BCLK adjustment to the timing calculations between processor and chipset guarantees host clock synchronization between the AGPset and processor core. The minimum and maximum values for this term are contained in Table 2-9.

Component timings for the Intel® Pentium® II processor and Intel® 440GX AGPset are contained in Table 2-10. The timing specifications are contained in the Intel® Pentium® II processor and Intel® 440GX AGPset Datasheets. These timing are for reference only.

Table 2-9. Intel® Pentium® II Processor and Intel® 440GX AGPset 100 MHz Timing Specifications

Timing Term	Intel® Pentium® II Processor	Intel® 440GX AGPset
Tco,max [ns]	4.66	4.45
Tco,min [ns]	0.71	0.80
Tsu [ns]	1.97	3.00
Th [ns]	1.61	-0.10
Tclk,min [ns]	0.77	Not applicable
Tclk,max [ns]	0.84	No applicable

Recommended values for system timings are contained in Table 2-10. Skew and jitter values for the clock generator device come from the CK97 clock driver specification. The PCB skew spec is based on the results of extensive simulations at Intel. The Tadj value is based on Intel’s experience with systems that use the Intel® Pentium® Pro processor and Intel® Pentium® II processor.

Table 2-10. Recommended 100 MHz System Timing Parameters

Timing Term	Value
Tskew,CLK [ns]	0.18
Tskew,PCB [ns]	0.15
Tjit [ns]	0.25
Tadj [ns]	0.40

The flight time requirements that result from using the component timing specifications and recommended system timings are summarized in Table 2-11. All component values should be verified against the current specifications before proceeding with analysis.

Table 2-11. Recommended 100 MHz System Flight Time Specs

Driver	Receiver	Tflight,min	Tflight,max
Intel® Pentium®II processor	AGPset	0.36	2.13
AGPset	Intel® Pentium®II	0.37	1.76
	processor
Intel® Pentium®II processor	Intel® Pentium®II	1.23	2.39
	processor

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