5520-DS04-405-R datasheet(60/90 Pages) BOARDCOM

60 / 90 page

BCM5220

Preliminary Data Sheet

04/20/04

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

Page 48

Auxiliary Mode 2 Register

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5220-DS04-405-R

Token Ring Mode

When enabled, the 100BASE-X unlock timer changes to allow long packets.

Block 10BASE-T Echo Mode

When enabled, during 10BASE-T half-duplex transmit operation, the TXEN signal does not echo onto the RXDV pin. The

TXEN echoes onto the CRS pin and the CRS deassertion directly follows the TXEN deassertion.

Traffic Meter LED Mode

When enabled, the Activity LEDs (ACTLED# and FDXLED# if full-duplex LED and interrupt LED modes are not enabled)

does not blink based on the internal LED clock (approximately 80 ms on time). Instead, they blink based on the rate of

Receive and Transmit activity. Each time a Receive or Transmit operation occurs, the LED turns on for a minimum of 5 ms.

During light traffic, the LED blinks at a low rate, while during heavier traffic the LEDs remains on.

Activity LED Force On

When asserted, the Activity LEDs (ACTLED# and FDXLED# if full-duplex LED and interrupt LED modes are not enabled) is

turned on. This bit has a higher priority than the Activity LED force Inactive, bit 4, register 1Dh.

Activity/Link LED Mode

When enabled, the RCVLED# output goes active upon acquiring link and pulses during Receive or Transmit activity.

Qualified Parallel Detect Mode

This bit allows the auto-negotiation/parallel detection process to be qualified with information in the Advertisement register.

If this bit is not set, the local BCM5220 device is enabled to auto-negotiate, and the far-end device is a 10BASE-T or

100BASE-X non-auto-negotiating legacy type, the local device auto-negotiate/parallel detects the far-end device, regardless

of the contents of its Advertisement register (04h).

If this bit is set, the local device compares the link speed detected to the contents of its Advertisement register. If the

particular link speed is enabled in the Advertisement register, the local device asserts link. If the link speed is disabled in this

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