Circuit Pack Descriptions
Issue 8.0 July 2002
7-19
Memory 7
Start-Up Memory. 7The start-up memory consists of 64 kilobytes of read-only
memory. The start-up memory contains the program that allows the processor to
load the executable code and data from the SYSCTL circuit pack into the
operating memory. This allows the processor to start up operation during a
power-up or a reset condition, or when initializing new software.
Operating Memory. 7ThemainoperatingmemoryoftheLAA28LNCTL(4MEG)
circuit pack consists of 4 megabytes of DRAM. Direct memory access (DMA)
allows the board controller to load the executable code and data received from the
SYSCTL circuit pack (via the line controller local area network) into the operating
memory during a power-up or reset condition, or when initializing new software.
Nonvolatile Memory. 7The nonvolatile memory consists of 128 bytes of
electrically-erasable programmable read-only memory (EEPROM). The
nonvolatile memory is used to store information about the history of the LNCTL
circuit pack such as the
CLEI
code and type/version information.
For more information about memory administration, refer to Volume I, Section 8,
"Administration and Provisioning."
Interface Circuitry 7
Line Controller Local Area Network Interface. 7The line controller local area
network (LCLAN) interface allows the LNCTL circuit pack to communicate with the
SYSCTL circuit pack.
Board Controller Local Area Network Interface. 7The board controller local area
network (BCLAN) interface allows the LNCTL circuit pack to communicate with
the board controllers on each circuit pack associated with a particular OC-48 high
speed line.
Power Circuitry 7
TheLNCTLcircuitpackreceivestwosourcesof−48 volts that are diode OR'd,
fused, and filtered. A modular DC-to-DC power converter produces +5 volts used
on the circuit pack. The power converter also provides two +5 volt sources for the
FAULT LEDs on the other circuit packs (associated with the same OC-48 high
speed line) if a power failure occurs.
The LNCTL circuit pack monitors the two −48 volt sources to the circuit pack. If the
LNCTL circuit pack detects a failure of the onboard fuse or power converter, the
red FAULT LED will light. If the fuse or power converter fails, the SYSCTL circuit
pack provides +5 volts to light the FAULT LED on the LNCTL circuit pack.
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