User Guide • PC3-ALLEGRO • CompactPCI
®
PlusIO CPU Board • Intel® i7-3xxx Processor
Hot Swap Detection
The CompactPCI® specification added the signal ENUM# to the PCI bus to allow board hot
swapping. This signal is routed to a GPIO (GPIO3 QM77 PCH) . An interrupt can be requested, if
ENUM# changes, caused by insertion or removal of a peripheral board.
Note that the PC3-ALLEGRO itself is not a hot swap device, because it makes no sense to remove the
system controller from a CompactPCI® system. However, it is capable to recognize the hot swap of
peripheral boards and to start software that is performing any necessary system reconfiguration.
Power Supply Status (DEG#, FAL#)
Power supply failures may be detected before the system crashes down by monitoring the signals
DEG# or FAL#. These active low lines are additions to the CompactPCI® specification and may be
driven by the power supply. DEG# signals the degrading of the supply voltages, FAL# there possible
failure. On the PC3-ALLEGRO DEG# is tied to VCC and FAL# is routed to QM77 PCH GPIO4.
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