rtd cpuModules CMA34CR, Руководство пользователя

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22 CMA34CR cpuModule BDM-610000083 Rev L
Selecting the Stack Order for the CMA34CR
There are several things to consider when selecting the order of boards in the stack. Before selecting the order,
be sure to determine which bus connector on each board is the “Active” bus. Typically, if a peripheral module has
both PCIe and PCI bus connectors, only the PCIe is active and the PCI is pass-through. The following is a list of
rules to use to determine the stack order:
1. The PCIe connectors above and below the CPU have completely separate signals. Therefore it is
possible to attach boards to the PCIe connector above and below the CPU.
2. Any board that uses a PCIe or SATA link must be within six boards of the CPU. Devices using PCIe Gen
3 should be the next card directly below/above the CPU for best performance. Devices using PCIe Gen
2 should not be more than 3 boards away from the CPU for best performance.
3. Any board that uses a USB 3.0 link must be within four boards of the CPU.
4. Any board that uses a USB 3.0 link must be closer to the CPU than any board that uses a USB 2.0 link.
5. To preserve power integrity, it is recommended that there be no more than six boards between the CPU
and the power supply.
6. In order to maintain maximum performance over the full temperature range, it is recommended that
a PCIe spacer be used between the CPU and any board immediately above it.
7. A maximum of four PCI boards may be attached to any PCI bus.
8. The PCIe to PCI bridge (if one exists in the stack) must be at one end of the PCI bus segment, and all of
the peripheral cards at the other end. There may be up to eight PCI pass-through connectors between
the PCIe to PCI bridge and the peripheral cards.
9. There must be no more than two boards between the first PCI peripheral and the last PCI peripheral.
If there are four PCI peripheral cards in a PCI bus segment, there may not be any PCI pass-through
connections between them.