5238-DS03-405-R datasheet(54/76 Pages) BOARDCOM

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BCM5238

Advance Data Sheet

1/31/03

Broa d c om Co rp o r a t i o n

Page 46

Auxiliary Mode Register

Document

5238-DS03-405-R

•

The MDIX Swap bit was manually set to a 1, or

•

The HP Auto-MDIX function is enabled and the BCM5238 has detected an MDI cross-over cable.

MDIX Manual Swap. When this bit is set to a 1, the MDI TD± and RD± signals for the BCM5238 are forced into being

swapped.

HP Auto-MDIX Disable. When this bit is set to a 1, the HP Auto-MDIX function is disabled in the BCM5238.

Manchester Code Error. Indicates that a Manchester code violation was received. This bit is only valid during 10BASE-T

operation.

End of Frame Error. Indicates that the end-of-frame (EOF) sequence was improperly received, or not received at all. This

error bit is only valid during 10BASE-T operation.

Auto-Negotiation Indication. A read-only bit that indicates whether auto-negotiation has been enabled or disabled on the

BCM5248. A combination of a 1 in bit 12 of the Control register and a logic 1 on the ANEN input pin is required to enable

auto-negotiation. When auto-negotiation is disabled, bit 15 of the Auxiliary Mode register returns a 0. At all other times, it

returns a 1.

Force 100/10 Indication. A read-only bit that returns a value of 0 when one of following two cases is true:

•

The ANEN pin is low AND the F100 pin is low, or

•

Bit 12 of the Control register has been written 0 AND bit 13 of the Control Register has been written 0.

When bit 2 of the Auxiliary Control register is 0, the speed of the chip is 10BASE-T. In all other cases, either the speed is

not forced (auto-negotiation is enabled), or the speed is forced to 100BASE-X.

Speed Indication. A read-only bit that shows the true current operation speed of the BCM5248. A 1 bit indicates

100BASE-X operation, whereas a 0 indicates 10BASE-T operation. Note that while the auto-negotiation exchange is

performed, the BCM5248 is always operating at 10BASE-T speed.

Full-Duplex Indication. A read-only bit that returns a 1 when the BCM5248 is in full-duplex mode. In all other modes, it

returns a 0.

AUXILIARY MODE REGISTER

Table 36: Auxiliary Mode Register (Address 29d, 1Dh)

Bit

Name

R/W

Description

Default

15:5

Reserveda

–

000h

Activity LED Disable

R/W

1 = Disable XMT/RCV Activity LED outputs

0 = Enable XMT/RCV Activity LED outputs

Link LED Disable

R/W

1 = Disable Link LED output

0 = Enable Link LED output

Reserveda

––

Block TXEN Mode

R/W

1 = Enable Block TXEN mode

0 = Disable Block TXEN mode

Note: R/W = Read/Write, RO = Read only, SC = Self Clear, LL = Latched Low, LH = Latched High, LL and LH Clear

after read operation. Use default values of reserved bit(s) when writing to reserved bit(s).

5238-DS03-405-R Datasheet(PDF) 54 Page - Broadcom Corporation.

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