Texas Instruments THUNDERSWITCH II TNETX4090 - Manual (Page 59)

TNETX4090
ThunderSWITCH II

9-PORT 100-/1000-MBIT/S ETHERNET

SWITCH
SPWS044E – DECEMBER 1997 – REVISED AUGUST 1999
59
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
internal wrap test (continued)
TNETX4090
08
07
06
05
04 03 02 01 00
NM
Figure 13. Internal Wrap Example
The operational status of the PHYs or external connections to the device do not have to be considered or
assumed good, when in internal loopback mode.
duplex wrap test
Duplex wrap test is similar to internal wrap mode (see Figure 13). The ports can be set to accept frame data
that is wrapped at the PHY. This permits network connections between the device and the PHY to be verified.
Any port can be the source port (not just the NM port as shown in Figure 14). By using multicast/broadcast
frames, traffic can be routed selectively between ports involved in the test or return the frame directly before
retransmission on the uplink. Software control of the external PHYs is required to configure them for loopback.
If the internal PCS is in use (port configured in PMA mode) loopback in PCSxControl also must be asserted.
This causes Mxx_EWRAP to be high, forcing external PMD into loopback mode.
Duplex frame-wrap test mode is selected by setting dpwrap in SysTest. When selected, the port is forced into
full duplex, allowing it to receive frames it transmits.
The switch is configured in the same manner as internal wrap.
TNETX4090
08
07
06
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04 03 02 01 00
NM
PHY
PHY
Figure 14. Duplex Wrap Example