TLK105 datasheet(32/99 Pages) TI

32 / 99 page

Valid Data

LOW Quality Data / Link Loss

First Link Failure

Occurrence

Link Drop

Signal

Link Loss

Indication

(Link LED)

TLK105

TLK106

SLLSEB8A – AUGUST 2012 – REVISED MARCH 2013

www.ti.com

Figure 5-3. TLK10x Link Loss Mechanism

As described in Figure 5-3, the TLK10x link loss mechanism is based on a time window search period, in

which the signal behavior is monitored. The T1 window is set by default to reduce typical link-drops to less

than 1ms.

The TLK10x supports enhanced modes that shorten the window called Fast Link Down mode. In this

mode, which can be configured in Control Register 3 (CR3), address 0x000B, bits 3:0, the T1 window is

shortened significantly, in most cases less than 10µs. In this period of time there are several criteria

allowed to generate link loss event and drop the link:

1. Count RX Error in the MII interface: When a predefined number of 32 RX Error occurrences in time

window of 10µs is reached the link will drop.

2. Count MLT3 Errors at the signal processing output (100BT uses MLT3 coding, and when a violation of

this coding is detected, an MLT3 error is declared). When a predefined number of 20 errors

occurrences in 10µs is reached the link will drop.

3. Count Low Signal Quality Threshold crossing (When the signal quality is under a certain threshold that

allows proper link conditions). When a predefined number of 20 occurrences in 10µs is reached, the

link will drop.

4. Signal/Energy loss indications. When Energy detector indicates Energy Loss, the link will be dropped.

Typical reaction time is 10µs.

The Fast Link Down functionality allows the use of each of these options separately or in any combination.

Note that since this mode enables extremely quick reaction time, it is more exposed to temporary bad link-

quality scenarios.

Architecture

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TLK105 Datasheet(PDF) 32 Page - Texas Instruments