DP83255AVF datasheet(16/96 Pages) NSC

Il numero della parte	DP83255AVF

Spiegazioni elettronici	PLAYER Device (FDDI Physical Layer Controller)

PDF	96 Pages

Scroll/Zoom	100%

Produttore elettronici	NSC [National Semiconductor (TI)]

Homepage	http://www.national.com

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16 / 96 page

40 Modes of Operation (Continued)

432 Internal Loopback

The Internal Loopback mode can be used to test the func-

tionality of the PLAYER device and to test the data paths

between the PLAYER and BMAC devices before ring inser-

tion

When in the Internal Loopback mode the PLAYER device

performs the following functions

Directs the output data of the Transmitter Block to the

input of the Receiver Block through internal paths (see

Figure 2-1 PLAYER Device Block Diagram)

Ignores the PMD Data Indicate pins (RXDg and RXCg)

Outputs Quiet symbols through the PMD Data Request

pins (TXDg) and

Outputs Quiet symbols through the External Loopback

Data pins (LBDg)

The level of the Quiet symbols transmitted through the

TXCg pins is programmable through the Transmit Quiet

Level bit of the Mode Register

The level of the Quiet symbols transmitted through the

LBDg pins is always high regardless of the Transmit Quiet

Level bit of the Mode Register

If both Internal Loopback and External Loopback modes are

selected Internal Loopback mode will have priority over Ex-

ternal Loopback mode

See

Figure 4-2 for a block diagram

TLF10386 – 16

FIGURE 4-2 Internal Loopback

DP83255AVF Scheda tecnica(PDF) 16 Page - National Semiconductor (TI)