Datasheet

 2017 Microchip Technology Inc. DS00002348A-page 37
KSZ8873MLL/FLL/RLL
3.13.2 NEAR-END (REMOTE) LOOPBACK
Near-end (Remote) loopback is conducted at either PHY port 1 or PHY port 2 of the KSZ8873MLL/FLL/RLL. The loop-
back path starts at the PHY port’s receive inputs (RXPx/RXMx), wraps around at the same PHY port’s PMD/PMA, and
ends at the PHY port’s transmit outputs (TXPx/TXMx).
Bit [1] of registers 26 and 42 is used to enable near-end loopback for ports 1 and 2, respectively. Alternatively, the MII
Management register 31, bit [1] can be used to enable near-end loopback.
The near-end loopback paths are illustrated in Figure 3-14.
FIGURE 3-13: FAR-END LOOPBACK PATH
FIGURE 3-14: NEAR-END (REMOTE) LOOPBACK PATH
PMD/PMA
PCS
MAC
Switch
MAC
PCS
PMD/PMA
TXP /
TXM
RXP /
RXM
Originating
PHY Port
Loop Back
PHY Port
TXP1/
TXM1
RXP1/
RXM1
RXP2/
RXM2
TXP2/
TXM2
PHY
Port 1
PHY
Port 2
PMD/PMA
PCS
MAC
Switch
MAC
PCS
PMD/PMA