HBLXT9785HC.C2 Cortina Systems Inc, HBLXT9785HC.C2 Datasheet - Page 132

• Manufacturer Part Number: HBLXT9785HC.C2
• Manufacturer: Cortina Systems Inc

Specifications of HBLXT9785HC.C2

• Lead Free Status / Rohs Status: Supplier Unconfirmed

LXT9785/LXT9785E
Datasheet
249241, Revision 11.0
16 April 2007
Figure 17
4.7.1
4.7.2
4.7.3
4.7.3.1
4.7.3.2
Figure 18
Cortina Systems
CLOCK
TxSYNC
TX
100 Mbps Serial MII Data Flow
SMII Reference Clock
The REFCLK operates at 125 MHz. The transmit and receive data and control streams
must always be synchronized to the REFCLK by the MAC and PHY. The LXT9785/
LXT9785E samples these signals on the rising edge of the REFCLK.
TxSYNC Pulse (SMII/SS-SMII)
The TxSYNC pulse delimits segment boundaries and synchronizes with REFCLK. The
MAC must continuously generate a TxSYNC pulse once every 10 REFCLK cycles. The
TxSYNC pulse signals the start of each new segment (see
Transmit Data Stream
Transmit data and control information are signaled in ten- bit segments. In 100 Mbps
mode, each segment contains a new byte of data. In 10 Mbps mode, the MAC must
repeat a 10M serial word ten times on TxData. The LXT9785/LXT9785E may sample that
serial word at any point.
The TxSYNC pulse signals the start of a new segment as shown in
Transmit Enable
The MAC must assert the TxEN bit in each segment of TxData, and de-assert TxENn after
the last segment of the packet.
Transmit Error
When the MAC asserts the TxER bit in 100BASE-X mode, the LXT9785/LXT9785E drives
“H” symbols onto the network interface. TxER does not have any function in 10M
operation.
Serial MII Transmit Synchronization
®
LXT9785 and LXT9785E Advanced 8-Port 10/100 Mbps PHY Transceivers
TxER
Serial Data Stream
To/From
MAC
TxEN
S0 S1
D3 D4 D5 D6 D7
D0 D1 D2
TXD0 TXD1
TX_EN &
TX_ER
RX_DV
CRS &
Status
Status
Insert
Strip
Bits
Bits
TXD2 TXD3 TXD4 TXD5 TXD6 TXD7
2 Nibbles Tx/Rx Data
D0 D1 D2 D3
D0 D1 D2 D3
4B/5B
Figure 21 on page
2 Symbols Tx/Rx Data
S0 S1 S2 S3 S4
S0 S1 S2 S3 S4
4.7 Serial MII Operation
Figure
18.
To/From
PMD
Sublayer
TxER
136).
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