MPC8544E datasheet(113/117 Pages) FREESCALE

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MPC8544E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 5

Freescale Semiconductor

113

System Design Information

21.10 Guidelines for High-Speed Interface Termination

This section provides guidelines for when the SerDes interface is either not used at all or only partly used.

21.10.1 SerDes Interface Entirely Unused

If the high-speed SerDes interface is not used at all, the unused pin should be terminated as described in

this section. However, the SerDes must always have power applied to its supply pins.

The following pins must be left unconnected (float):

•

SD_TX[0:7]

•SD_TX[0:7]

The following pins must be connected to GND:

•SD_RX[0:7]

•SD_REF_CLK

•

SD_REF_CLK

21.10.2 SerDes Interface Partly Unused

If only part of the high speed SerDes interface pins are used, the remaining high-speed serial I/O pins

should be terminated as described in this section.

The following pins must be left unconnected (float) if not used:

•

SD_TX[0:7]

•SD_TX[0:7]

The following pins must be connected to GND if not used:

•SD_RX[0:7]

•SD_REF_CLK

•

SD_REF_CLK

21.11 Guideline for PCI Interface Termination

PCI termination, if not used at all, is done as follows.

Option 1

•

If PCI arbiter is enabled during POR,

•

All AD pins will be driven to the stable states after POR. Therefore, all ADs pins can be floating.

•

All PCI control pins can be grouped together and tied to OVDD through a single 10-kΩ resistor.

•

It is optional to disable PCI block through DEVDISR register after POR reset.

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