Pcirst# Implementation; P64H2 Power Sequencing Requirement; Pci/Pci-X (Vcc_3.3) Capacitor Placement - Intel Xeon Design Manual

Platform Power Delivery Guidelines
Figure 12-23. 3.3V PCI/PCI-X (VCC_3.3) Capacitor Placement
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NOTE: The outlined area in the figure is the 3.3 V plane. Place at least five 0.1 µ F capacitors in this area.
12.5.3

PCIRST# Implementation

PCI-X requires a 100 ms delay from valid power (PWRGD) to reset deassertion (PCIRST#). The
system design must ensure this requirement is met.
The P64H2 reset must be deasserted within 60 ns of the MCH reset deassertion. Intel strongly
recommends the customer to measure this timing relationship on their board. Failure to meet this
guideline may result in a system failing to boot.
12.5.4

P64H2 Power Sequencing Requirement

3.3 V and 1.8 V must be valid before the first CLK66 pulse is drive to the P64H2. This can be
garunteed by gating the CK408 cocks using a power good signal from the 1.8 V regulator.
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0.1uF
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Design Guide