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The meanings of the eight MPU (microprocessor unit) activity monitoring LEDs
are as follows:
Mnemonic
TX
RX
MN
DL
RO
Q
IT
ST
MPU Activity in Progress
On when the LANIC is processing and transmitting a frame.
On when the LANIC is processing a frame that was received at
an address which the LANIC recognized as its own.
On when the LANIC is monitoring all link activity, or is
monitoring activity sent to a particular address not its own.
On when the LANIC receives a command from the SPU
(system processor unit) to start downloading operating
firmware. Off when the SPU commands the MPU to begin to
execute the downloaded feature.
On when ROM-resident firmware is being executed by the
MPU. Off when downloaded firmware is being executed by
the MPU.
On when the MPU is quiescent. During such times, it is
checking for activity that requires attention.
On when the MPU is executing an idle test of internal LANIC
circuitry. During idle test, the MPU tests hardware on the
LANIC that can be exercised without affecting readiness to
process frames. The idle test also runs before the node becomes
operational on the link.
On when the MPU is executing the ROM-resident self test,
which verifies proper operation of the LAN hardware
subsystem. \Vhen the ST LED is lit, the other seven MPU
activit.y LEOs are interpreted as self test progress and failure
indicators. rather than according to the mnemonics given above.
For details of the use of self test, see Chapter 4 of this manual
and the LA N/3000 Diagnostic and Trouhlcshoo/ing Guide. part
number 30242-90003.
The seven AUI activity LEOs are intended to be used as aids in determining
activity on the network, and whether the source of this activity is this node or
some other node on the network. These seven LEOs monitor the four functions
shown below.
Principles of Operation
3-17
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