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Troubleshooting the LAN Connection
Troubleshooting the Initial Connection
The following table describes each bit in the status number.
Status Bits
Bit 0 The internal registers of the LAN IC are loaded with known test
values and then are read. If this bit is not set, it implies that the LAN
IC is operating properly and that the microproce ssor can
communicate with the LAN IC. If this bit is set, then the LAN module
is not operational and must be replaced.
Bit 1 he CAM (Content Addressable Memory) bit reports whether the
LAN address can be written from the LAN module Static RAM
(SRAM) to the internal memory of the LAN IC. Also, the CAM bit
reports whether the LAN address can be written to SRAM from the
LAN IC. If this bit is not set, it implies that both the SRAM and the
LAN IC internal memory are able to recognize and store the LAN
address. If this bit is set, then the LAN module is not operational
and must be replaced.
Bit 2 If this bit is not set, then the self-test has detected that the LAN
cable is properly connected to the LAN board. If this bit is set, then
the physical connection of the LAN cable must be checked.
Bit 3 If the Termination bit is set, then the self-test has detected an
excessive number of collisions. The most probable cause of
excessive collisions is an improperly terminated LAN cable.
Provide a proper termination of the LAN cable according to the
LAN topology being used.
Bit 4 The MAC (Media Access Control) bit indicates whether the Media
Access Control unit on the LAN IC is functioning. If this bit is not
set, it implies that both the transmit functions and receive functions
of the LAN IC are operating properly. If this bit is set, then the LAN
module is not able to properly transmit and receive packets and
must be replaced.
Bit 5 The ENDEC (Encoder/Decoder) bit indicates whether the encoder/
decoder internal to the LAN IC is functioning. The encoder/decoder
is the interface between the MAC and the Ethernet tr ansceiver. If
this bit is set, then the ENDEC is not operating properly and the LAN
module must be replaced.