PC6-TANGO • CompactPCI
®
PlusIO • Intel® Atom™ E39xx Processor (APL-I SoC)
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 (ISH GPIO7 APL-I SoC) . An interrupt can be requested, if
ENUM# changes, caused by insertion or removal of a peripheral board.
Note that the PC6-TANGO 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 (PWR_FAIL#)
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 PC6-TANGO DEG# is pulled to VCC and FAL# is routed to APL-I SoC GPIO17.
As an option a circuit can be stuffed on PC6-TANGO to use this signal as an output to drive PSON#
of a power supply. With this option and the related external wiring it is possible to switch off the main
power supply when the system powers down to state S4. To restart the system, the PSON# line must
be pulled down manually for a second approximately, e.g. by an external push-button.
The use of this signal as PWR_FAIL# or PSON# is mutually exclusive.
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