Decchip 21040 Ethernet Controller Tests - DEC Digital Alpha VME 4/224 User Manual

DECchip 21040 Ethernet Controller Tests

DECchip 21040 Ethernet Controller Tests
These diagnostics verify that the internal and external loopback mechanisms
are properly operating in the DECchip 21040 Ethernet controller chip as well as
performing writes and reads to all configuration registers.
Ethernet Internal Loopback Test
The NI internal loopback test transmits Ethernet packets from the transmit ring
in main memory, loops them back at the MAC layer and returns them to the
receive ring in main memory. No traffic is put on the network cable.
The NI external loopback test transmits Ethernet packets from the transmit ring
in main memory and places them on the network medium (twisted pair cable). It
concurrently listens to the line which carries its own transmissions and returns
them to the receive ring in main memory. Received packets not identified as test
packets are discarded for the duration of the test.
To run the external loopback test, you must use a 10baseT loopback
connector (H4082-AA). The external loopback test does not run if the
device is connected to an open network.
These two tests check the following logic respectively:
• The device's internal logic up to but not including the Ethernet transmission
logic.
• The on-chip transmit/receive circuitry and the passive external components
that connect to the twisted pair interface.
Console Command
• For internal loopback: niil_diag -t 1
• For external loopback: niil_diag -t 2
Command Option:
-dd: print detailed test information on each pass.
4–16 Diagnostics
Note