TLK105 Datasheet, PDF (14/99 Pages) Texas Instruments – Industrial Temp, Single Port 10/100Mbs Ethernet Physical Layer Transceiver

TLK105
TLK106
SLLSEB8A – AUGUST 2012 – REVISED MARCH 2013
www.ti.com
3.9.2 Far-End Loopback
Far-end (Reverse) loopback is a special test mode to allow testing the PHY from the link-partner side. In
this mode, data that is received from the link partner passes through the PHY's receiver, looped back on
the MII and transmitted back to the link partner. Figure 3-6 shows Far-end loopback functionality.
MAC/
Switch
M
I
PCS
I
Signal
Process
PHY Digital
PHY
AFE
XFMR _{CAT5 Cable}
&
Link Partner
RJ45
Reverse Loopback
Figure 3-6. Block Diagram, Far-End Loopback Mode
The Reverse Loopback mode is selected by setting bit 4 in the BIST Control Register (BISCR), MII
register address 0x0016.
While in Reverse Loopback mode the data is looped back and also transmitted onto the MAC Interface
and all data signals that come from the MAC are ignored.
Table 3-5 describes the operating modes for Far-End Loopback.
Table 3-5. Far-End Loopback Modes
Operational MAC Int.
MII Mode
Operational Setting Force/ANEG 10/100
RMII Mode
Force/ANEG 10
14
Hardware Configuration
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