EMAC Functional Architecture

www.ti.com

In the case of the S3MII switch, where the switch has only one TX_SYNC for all ports, external logic is needed to synchronize the TX_SYNC signals from multiple ports or TCI6486/C6472 devices. The TXD signal from the multiple ports should also be synchronized using external logic since the clock-phase relation of different TCI6486/C6472 devices can be different. Figure 8 demonstrates the example mutli-PHY configuration for S3MII.

Figure 8. S3MII Switch Configuration

 

 

 

 

S3MII

 

 

 

 

switch

 

 

 

 

TX_CLK

 

Device #1

 

TX_SYNC

 

 

 

 

 

TXD

 

P0_TXD

 

 

TX_SYNC

 

P0_RXD

 

 

TX_CLK

 

 

 

 

RXD

 

 

 

 

RX_SYNC

 

 

 

 

RX_CLK

 

 

 

MHZ_125_CLK

 

 

 

Device #2

 

 

 

 

TXD

 

P1_TXD

 

 

TX_SYNC

External

P1_RXD

 

 

TX_CLK

logic

 

 

 

element

 

 

 

 

 

 

 

RXD

 

 

 

 

RX_SYNC

 

 

 

 

RX_CLK

 

 

 

MHZ_125_CLK

 

 

 

Device #n

 

 

 

 

TXD

 

Pn_TXD

 

 

TX_SYNC

 

Pn_RXD

 

 

TX_CLK

 

 

 

 

RXD

 

 

 

 

RX_SYNC

 

 

 

 

RX_CLK

 

 

 

MHZ_125_CLK

Low-skew

 

 

 

 

RX_SYNC

 

 

 

buffer

 

 

 

 

 

125-MHz

125-MHz

 

 

 

zero-delay

Zero-delay

 

 

XO

RX_CLK

 

clock buffer

clock buffer

 

 

 

28

C6472/TCI6486 EMAC/MDIO

SPRUEF8F –March 2006 –Revised November 2010

Submit Documentation Feedback

Copyright © 2006–2010, Texas Instruments Incorporated

Page 28
Image 28
Texas Instruments TMS320TCI6486 manual S3MII Switch Configuration