T2080NXE8MQLB View Datasheet(PDF) - NXP Semiconductors.

Part Name

Description

Manufacturer

T2080NXE8MQLB

T2080 QorIQ integrated multicore communications processor

NXP Semiconductors. 

Electrical characteristics

3.19.2.1 SerDes spread-spectrum clock source recommendations

SDn_REF_CLKn_P/SDn_REF_CLKn_N are designed to work with spread-spectrum

clock for PCI Express protocol only with the spreading specification defined in Table 59.

When using spread-spectrum clocking for PCI Express, both ends of the link partners

should use the same reference clock. For best results, a source without significant

unintended modulation must be used.

For SATA protocol, the SerDes transmitter does not support spread-spectrum clocking.

The SerDes receiver does support spread-spectrum clocking on receive, which means the

SerDes receiver can receive data correctly from a SATA serial link partner using spread-

spectrum clocking

The spread-spectrum clocking cannot be used if the same SerDes reference clock is

shared with other non-spread-spectrum supported protocols. For example, if the spread-

spectrum clocking is desired on a SerDes reference clock for PCI Express and the same

reference clock is used for any other protocol such as SATA/SGMII/QSGMII/SRIO/

XAUI due to the SerDes lane usage mapping option, spread-spectrum clocking cannot be

used at all.

Table 59. SerDes spread-spectrum clock source recommendations1

Parameter

Frequency modulation

Frequency spread

Notes:

1. At recommended operating conditions. See Table 3.

2. Only down-spreading is allowed.

Min

30

+0

Max

33

-0.5

Unit

kHz

%

Notes

-

2

3.19.2.2 SerDes reference clock receiver characteristics

This figure shows a receiver reference diagram of the SerDes reference clocks.

QorIQ T2080 Data Sheet, Rev. 3, 03/2018

100

NXP Semiconductors

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