DP83251 datasheet(23/96 Pages) NSC

23 / 96 page

50 Registers (Continued)

CONFIGURATION REGISTER (CR)

The Configuration Register controls the Configuration Switch Block and enablesdisables both the A and B Indicate output

ports

Note that the B

Indicate output port is offered only on the DP83255 (for Dual Attach Stations) and not in the DP83251 (for

Single Attach Stations)

For further information refer to Section 33 Configuration Switch

ACCESS RULES

ADDRESS

READ

WRITE

01h

Always

BIE

AIE

TRS1

TRS0

BIS1

BIS0

AIS1

AIS0

Bit

Symbol

Description

D0 D1

AIS0 AIS1

INDICATE SELECTOR k0 1l

The A

Indicate Selector k0 1l bits select one of the four

Configuration Switch data buses for the A

Indicate output port (AIP AIC AID k70l)

AIS1

AIS0

PHY Invalid Bus

Receiver Bus

Request Bus

D2 D3

BIS0 BIS1

INDICATE SELECTOR k0 1l

The B

Indicate Selector k0 1l bits select one of the four

Configuration Switch data buses for the B

Indicate output port (BIP BIC BID k70l)

BIS1

BIS0

PHY Invalid Bus

Receiver Bus

Request Bus

Note

Even though this bit can be set andor cleared in the DP83251 (for Single Attach Stations) it will not affect

any IOs since the DP83251 does not offer a B

Indicate port

D4 D5

TRS0 TRS1

TRANSMIT REQUEST SELECTOR k0 1l

The Transmit Request Selector k0 1l bits select

one of the four Configuration Switch data buses for the input to the Transmitter Block

TRS1

TRS0

PHY Invalid Bus

Receiver Bus

Request Bus

Note

If the PLAYER device is in Active Transmit Mode (ie the Transmit Mode bits (TMk20l) of the Current

Transmit State Register (CTSR) are set to 000) and the PHY Invalid Bus is selected then the PLAYER device will

transmit a maximum of four Halt symbol pairs and then continuous Idle symbols due to the Repeat Filter

AIE

INDICATE ENABLE

0 Disables the A

Indicate output port The A

Indicate port pins will be at TRI-STATE when

the port is disabled

1 Enables the A

Indicate output port (AIP AIC AIDk70l)

BIE

INDICATE ENABLE

0 Disable the B

Indicate output port The B

Indicate port pins will be at TRI-STATE

when the port is disabled

1 Enables the B

Indicate output port (BIP BIC BIDk70l)

Note

Even though this bit can be set andor cleared in the DP83251 (for Single Attach Stations) it will not affect

any IOs since the DP83251 does not offer a B

Indicate port

DP83251 Datasheet(PDF) 23 Page - National Semiconductor (TI)

DP83251 Datasheet(HTML) 23 Page - National Semiconductor (TI)

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