Datasheet

LAN8710A/LAN8710AI

DS00002164B-page 36  2016 Microchip Technology Inc.

is routed through the PCS and PMA layers into the PMD sublayer before it is looped back. The COL signal will be inac-

tive in this mode, unless Collision Test is enabled in the Basic Control Register. The transmitters are powered down

regardless of the state of TXEN.

FIGURE 3-9: NEAR-END LOOPBACK BLOCK DIAGRAM

SMSC

Ethernet Transceiver

10/100

Ethernet

MAC

CAT-5

XFMR

Digital

RXD

TXD

Analog

3.8.9.2 Far Loopback

Far loopback is a special test mode for MDI (analog) loopback as indicated by the blue arrows in Figure 3-11. The far

loopback mode is enabled by setting the FARLOOPBACK bit of the Mode Control/Status Register to “1”. In this mode,

data that is received from the link partner on the MDI is looped back out to the link partner. The digital interface signals

on the local MAC interface are isolated.

FIGURE 3-10: FAR LOOPBACK BLOCK DIAGRAM

Far-end system