adm6995 ETC-unknow, adm6995 Datasheet - Page 17

• Manufacturer Part Number: adm6995
• Description: Port 10/100 Mb/s Single Chip Ethiernet Switch Controller
• Manufacturer: ETC-unknow

ADM6995L
ADMtek Inc.
Chapter 3 Function Description
3.1
3.2
3.3
3.4
Functional Descriptions
The ADM6995L integrates five 100Base-X physical sub-layer (PHY), 100Base-TX
physical medium dependent (PMD) transceivers, five complete 10Base-T modules and
memory into a single chip for both 10Mbits/s, 100Mbits/s Ethernet switch operation. It
also supports 100Base-FX operation through external fiber-optic transceivers. The device
is capable of operating in either Full Duplex mode or Half-Duplex mode in 10Mbits/s and
100Mbits/s. Operational modes can be selected by hardware configuration pins, software
settings of management registers, or determined by the on-chip auto negotiation logic.
The ADM6995L consists of three major blocks:
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10/100M PHY Block
The 100Base-X section of the device implements the following functional blocks:
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100Base-X Module
The ADM6995L implements 100Base-X compliant PCS and PMA and 100Base-TX
compliant TP-PMD as illustrated in Figure 2. Bypass options for each of the major
functional blocks within the 100Base-X PCS provides flexibility for various applications.
100Mbits/s PHY loop back is included for diagnostic purpose.
100Base-X Receiver
The 100Base-X receiver consists of functional blocks required to recover and condition
the 125Mbits/s receive data stream.
receiving state machine diagram as given in ANSI/IEEE Standard 802.3u, Clause 24. The
125Mbits/s receive data stream may originate from the on-chip twisted-pair transceiver in
a 100Base-TX application. Alternatively, the receive data stream may be generated by an
external optical receiver as in a 100Base-FX application.
The receiver block consists of the following functional sub-blocks :
10/100M PHY Block
Switch Controller Block
Built-in SSRAM
100Base-X physical coding sub-layer (PCS)
100Base-X physical medium attachment (PMA)
Twisted-pair transceiver (PMD)
The 100Base-X and 10Base-T sections share the following functional blocks.
Clock synthesizer module
IEEE 802.3u auto negotiation
The ADM6995L implements the 100Base-X
Function Description
3-1