lxt9785 Intel Corporation, lxt9785 Datasheet - Page 139

• Manufacturer Part Number: lxt9785
• Description: Advanced 8-port 10/100 Mbps Phy Transceivers
• Manufacturer: Intel Corporation

4.8
4.8.1
Datasheet
Document Number: 249241
Revision Number: 007
Revision Date: August 28, 2003
Figure 22. Intel
Figure 23. Intel
Note: The BGA15 package does not support the RMII interface.
RMII Operation
The LXT9785/LXT9785E provides an independent Reduced MII port for each network port. Each
RMII uses four signals to pass received data to the MAC: RxDatan<1:0>, RxERn, and CRS_DVn
(where n reflects the port number). Three signals are used to transmit data from the MAC:
TxDatan_<1:0> and TxENn. Both receive and transmit signals are clocked by REFCLK. Data
transmission across the RMII is implemented in di-bit pairs which equal a 4-bit wide nibble.
RMII Reference Clock
The LXT9785/LXT9785E requires a 50 MHz reference clock (REFCLK). The device samples the
RMII input signals on the rising edge of REFCLK and drives RMII output signals on the falling
edge.
®
®
LXT9785/LXT9785E SS-SMII Transmit Timing
LXT9785/LXT9785E SS-SMII Receive Timing
LXT9785 and LXT9785E Advanced 8-Port 10/100 Mbps PHY Transceivers
TxCLK
TxSYNC
TxData
TxCLK
TxSYNC
TxData
All signals are synchronous to the clock
RxCLK
RxData
RxSYNC
RxCLK
RxData
All signals are synchronous to the clock
RxSYNC
TXER TXEN
TXER
CRS RXDV
CRS
TXEN
RXDV
Frcerr Speed
TXD0 TXD1
RXER Speed
RXD0 RXD1
TXD2
Dplx
RXD2
Dplx
TXD3 TXD4 TXD5
LINK
RXD3 RXD4 RXD5
LINK
Jabr
Jabr
UPnib
TXD6
RXD6
FlsCar
TXD7
RXD7
TXER
TXER
CRS
CRS
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