ADM6996L-AA-T-1 Lantiq, ADM6996L-AA-T-1 Datasheet - Page 18

• Manufacturer Part Number: ADM6996L-AA-T-1
• Manufacturer: Lantiq

Specifications of ADM6996L-AA-T-1

• Lead Free Status / RoHS Status: Supplier Unconfirmed

3.4.8
The RXER signal is used to communicate receiver error conditions. While the receiver is in a state of holding
RXDV asserted, the RXER will be asserted for each code word that does not map to a valid code-group.
3.4.9
The 100Base-X link monitor function allows the receiver to ensure that reliable data is being received. Without
reliable data reception, the link monitor will halt both transmit and receive operations until such time that a valid
link is detected.
The ADM6996L/LX performs the link integrity test as outlined in IEEE 100Base-X (Clause 24) link monitor state
diagram. The link status is multiplexed with 10Mbits/s link status to form the reportable link status bit in the serial
management register 1h, and driven to the LNKACT pin.
When persistent signal energy is detected on the network, the logic moves into a Link-Ready state after
approximately 500 micro secs, and waits for an enable from the auto negotiation module. When received, the link-
up state 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.
3.4.10
Carrier sense (CRS) for 100Mbits/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 de-asserted. In repeater mode, CRS is only asserted
due to receive activity. CRS is intended to encapsulate RXDV.
3.4.11
A Bad Start of Stream Delimiter (Bad SSD) is an error condition that occurs in the 100Base-X receiver if a carrier
is detected (CRS asserted) and a valid /J/K set of code-group (SSD) is not received.
If this condition is detected, then the ADM6996L/LX will assert RXER and present RXD[3:0] = 1110 to the internal
MII for the cycles that correspond to received 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 de-asserted.
3.4.12
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 be receiving 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 1
group of 84 1
3.5
The ADM6996L/LX 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 magnetic for both the 10Base-T and the 100Base-TX transmissions with a simple RC
component connection. The individually wave-shaped 10Base-T and 100Base-TX transmit signals are
multiplexed in the transmission output driver selection.
Data Sheet
Receive Errors
100Base-X Link Monitor
Carrier Sense
Bad SSD Detection
Far-End Fault
100Base-TX Transceiver
B
’s followed by a single 0
B
. This is referred to as the FEFI idle pattern.
18
Function Description
Rev. 1.13, 2005-11-22
ADM6996L/LX
Data Sheet
B
’s to a