ADM7001XACT1XP Lantiq, ADM7001XACT1XP Datasheet - Page 29

• Manufacturer Part Number: ADM7001XACT1XP
• Manufacturer: Lantiq

Specifications of ADM7001XACT1XP

• Lead Free Status / RoHS Status: Supplier Unconfirmed

is entered, and the transmission and reception logic blocks become active. Should auto negotiation be disabled,
the link integrity logic moves immediately to the link-up state after entering the link-ready state.
Carrier Sense
Carrier sense (CRS) for 100 Mbits/s operation is asserted upon the detection of two non contiguous zeros
occurring within any 10-bit boundary of the received data stream.
The carrier sense function is independent of symbol alignment. In switch mode, CRS is asserted during either
packet transmission or reception. For repeater mode, CRS is asserted only during packet reception. When the idle
symbol pair is detected in the received data stream, CRS is deasserted. In repeater mode, CRS is only asserted
due to receive activity. CRS is intended to encapsulate RXDV.
Bad SSD Detection
A bad start of stream delimiter (Bad SSD) is an error condition that occurs in the 100Base-X receiver if carrier is
detected (CRS asserted) and a valid /J/K set of code-group (SSD) is not received.
If this condition is detected, the ADM7001 will assert RXER and present RXD[3:0] = 1110 to the internal MII for
the cycles hat correspond to receive 5B code-groups until at least two idle code-groups are detected. Once at least
two idle code groups are detected, RXER and CRS become deasserted.
Far-End Fault
Auto negotiation provides a mechanism for transferring information from the Local Station to the link Partner that
a remote fault has occurred for 100Base-TX. As auto negotiation is not currently specified for operation over fiber,
the far end fault indication function (FEFI) provides this capability for 100Base-FX applications.
A remote fault is an error in the link that one station can detect while the other cannot. An example of this is a
disconnected wire at a station’s transmitter. This station will receive valid data and detect that the link is good via
the link integrity monitor, but will not be able to detect that its transmission is not propagating to the other station.
A 100Base-FX station that detects such a remote fault may modify its transmitted idle stream from all ones to a
group of 84 ones followed by a single 0. This is referred to as the FEFI idle pattern.
The FEFI function is controlled by bit 3 of register 11
high level during power on reset. If the FEFI function is enabled the ADM7001 will halt all current operations and
transmit the FEFI idle pattern when FOSD signal is de-asserted following a good link indication from the link
integrity monitor. FOSD signal is generated internally from the internal signal detect circuit. Transmission of the
FEFI idle pattern will continue until link up signal is asserted. If three or more FEFI idle patterns are detected by
the ADM7001, bit 4 of the Basic mode status register (address 1h) is set to one until read by management.
Additionally, upon detection of far end fault, all receive and transmit MII activities are disabled/ignored.
3.1.3
ADM7001 implements a TP-PMD compliant transceiver for 100Base-TX operation. The differential transmit driver
is shared by the 10Base-T and 100Base-TX subsystems. This arrangement results in one device that uses the
same external magnetics for both the 10Base-T and the 100Base-TX transmission with simple RC component
connections. The individually wave-shaped 10Base-T and 100Base-TX transmit signals are multiplexed in the
transmission output driver selection.
ADM7001 100Base-TX transmission driver implements MLT-3 translation and wave-shaping functions. The
rise/fall time of the output signal is closely controlled to conform to the target range specified in the ANSI TP-PMD
standard.
3.1.4
Signal is received through PECL receiver inputs from fiber transceiver, and directly passed to clock recovery circuit
for data/clock recovery. Scrambler/de-scrambler is bypassed in 100Base-FX.
Data Sheet
100Base-TX Transmitter
100Base-FX Receiver
H
. It is initialized to 1 (encoded) if the SELFX pin is at logic
29
Function Description
Rev. 1.07, 2005-09-12
Data sheet
ADM7001