DP83255AVF datasheet(15/96 Pages) NSC

15 / 96 page

40 Modes of Operation

The PLAYER device can operate in 4 basic modes RUN

STOP LOOPBACK and CASCADE

41 RUN MODE

RUN is the normal mode of operation

In this mode the PLAYER device is configured to be con-

nected to the media via the Fiber Optic Transmitter and

Receiver at the Serial Interface It is also connected to other

PLAYER device(s) andor BMAC device(s) via the Port A

and Port B Interfaces

While operating in the Run mode the PLAYER device re-

ceives and transmits Line States (Quiet Halt Master Idle)

and frames (Active Line State)

42 STOP MODE

The PLAYER device operates in the STOP mode while it is

being initialized or configured

The PLAYER device is also reset to the STOP mode auto-

matically when the RST pin (pin 71 on the DP83251 and pin

111 on the DP83255) is set to ground

When in STOP mode the PLAYER device performs the fol-

lowing functions

Resets the Repeat Filter

Resets the Smoother

Resets the Receiver Block Line State Counters

Flushes the Elasticity Buffer

Forces Line State Unknown in the Receiver Block

Outputs LSU symbol pairs (0 1 0011 1010) through

the PHY Data Indicate pins (AIP AIC AID k70l BIP

BIC BIDk70l)

Outputs Quiet symbol pairs through the PMD Data Re-

quest pins (TXDg)

Resets all Control Bus register contents to zero or de-

fault values

43 LOOPBACK MODE

The PLAYER device provides three types of loopback tests

Configuration Switch Loopback Internal Loopback and Ex-

ternal Loopback These Loopback modes can be used to

test different portions of the device

431 Configuration Switch Loopback

The Configuration Switch Loopback can be used to test the

data paths of the BMAC device(s) that are connected to the

PLAYER device before transmitting and receiving data

through the network

In the Configuration Switch Loopback mode the PLAYER

device performs the following functions

Selects Port A PHY Request Data Port B PHY Request

Data or PHY Invalid to connect to Port A PHY Indicate

Data via the A

IND Mux

Selects Port A PHY Request Data Port B PHY Request

Data or PHY Invalid to connect to Port B PHY Indicate

Data via the B

IND Mux

Connects data from the Receiver Block to the Transmit-

ter Block via the Transmitter

Mux (The PLAYER device

is repeating incoming data from the media in the Configu-

ration Switch Loopback mode)

See

Figure 4-1a and 4-1b for block diagrams

TLF10386 – 42

FIGURE 4-1a Configuration Switch

Loopback for DP83255

TLF10386 – 43

FIGURE 4-1b Configuration Switch

Loopback for DP83251

FIGURE 4-1

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