82583V Datasheet, PDF (363/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

Diagnostics—82583V GbE Controller
13.4
Note:
Note:
Note:
Loopback Operations
Loopback operations are supported by the 82583V to assist with system and device
debug. Loopback operation can be used to test transmit and receive aspects of
software device drivers, as well as to verify electrical integrity of the connections
between the 82583V and the system (such as, PCIe bus connections, etc.). Loopback
operation is supported as follows:
Configuration for loopback operation varies depending on the link configuration being
used.
• MAC Loopback while operating with the internal PHY
• Loopback – To configure for loopback operation, the RCTL.LBM should remain
configured as for normal operation (set=00b). The PHY must be programmed,
using MDIO accesses to its MII management registers, to perform loopback within
the PHY.
All loopback modes are only allowed when the 82583V is configured for full-duplex
operation.
MAC loopback is not functional when the MAC is configured to work at 10 Mb/s.
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