DP83256 datasheet(32/144 Pages) NSC

tên linh kiện	DP83256

Giải thích chi tiết về linh kiện	PLAYERa??Device (FDDI Physical Layer Controller)

PDF	144 Pages

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nhà sản xuất	NSC [National Semiconductor (TI)]

Trang chủ	http://www.national.com

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32 / 144 page

40 Modes of Operation (Continued)

Short Internal Loopback

The Short Internal Loopback mode can be used to test the

functionality of the PLAYERa device not including the

Clock Recovery function and to test the data paths be-

tween the PLAYERa device and MACSI devices before

ring insertion

When in the Short Internal Loopback mode the PLAYERa

device performs the following functions

Directs the output data of the Transmitter Block to the

input of the Receiver Block through an internal path

Ignores the PMD Data Indicate pins (PMIDg)

Outputs Quiet symbols through the PMD Data Request

pins (PMRDg)

The level of the Quiet symbols transmitted through the

PMRDg pins during loopback is automatically set to the

transmitter off level

If both Short Internal Loopback and Long Internal Loopback

modes are selected Long Internal Loopback mode will

have priority over Short Internal Loopback mode This is the

longest loopback path within the PLAYERa device

See

Figure 4-3 Short Internal Loopback

TLF11708 – 25

FIGURE 4-3 Short Internal Loopback

DP83256 bảng dữ liệu(PDF) 32 Page - National Semiconductor (TI)