Using PEX 8648 SMA Based (SI) Card White Paper – Version 1.3
© 2010 by PLX Technology, Inc. All Rights Reserved
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Figure 4. PEX 8648 SMA Card Ref Clock Input Options
The default PCB configuration has Port 0 – the PCIe connector port – as the upstream connection. This
means it must be the port that points towards the PCIe root complex. This configuration allows a user to
directly connect the PCB into a PCIe system chassis, observe signals and begin using PLX software for
register manipulation without an I
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C controller.
To move from signal observation to an adjustable PCIe link, .bin files are supplied, which demonstrate
how to convert the SMA port to the upstream link and operate as a standard PCIe link – progressing thru
link negotiation, and yet hold the desired channel tuning values. The various EEPROM .bin files contain
key SerDes registers used for:
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Upstream Port configuration
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Signal
Swing
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De-emphasis
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RX equalization
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Electrical Idle threshold adjustment
With this method of operation (using EEPROM to set values), the EEPROM is programmed or adjusted
for the desired settings and the system is then reset to verify operation.
