Kontron cPCI-MXS64GX, Техническое справочное руководство

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cPCI-MXS64GX Technical Reference manual
1.4
1.3. HOT SWAP CAPABILITY
The cPCI-MXS64GX supports Hot Swap capability which means that hot swappable
boards can be removed from or installed in the system while online (without powering-
down the system).
Hot Swap consists of board hardware with the Hot Swap additions to the Hardware
Connection Layer, and the Hot-Plug Service. Upon insertion of the board (any hot
swappable board but the system host, cPCI-MXS64GX, the hardware connection layer will
initialize the board and the Hot-Plug Service provides the means for reconfiguring the
system.
High Availability is an attribute of a system designed to keep running (maintain
availability) in the event of a system component failure. To provide a high degree of
availability, a system requires a higher degree of control.
High Availability (HA) uses a higher degree of control than just indicating insertion and
extraction. HA systems are able to control the Hardware Connection Process. To do this,
the capabilities of the system are extended to allow software control of a board’s hardware
connection state. A hardware connection sequence is made possible through the use of
different pin lengths and the process ends with the mating of the shortest pin (BD_SEL#).
The platform adds hardware to provide more control of each board’s Hardware Connection
Layer. The signals: BD_SEL#, HEALTHY#, and PCI_RST# are used to individually
control each slot of the system.
BD_SEL# is one of the shortest pins. This pin is the last to mate and the first
to break contact. This ensures that the sensing of its connection
takes place at a time when all other pins are reliably connected. It is
driven low to enable power on. For systems not implementing
hardware connection control, it is grounded on the backplane.
HEALTHY# is used to acknowledge the health of the board. It signals that a
board is suitable to be released from reset and allowed onto the PCI
bus. In an HA system, the software can detect a faulty board when
it fails to assert HEALTHY# after BD_SEL# has been asserted. A
running board can also become not healthy at any time.
PCI_RST# as defined by the CompactPCI
®
Specification, is a signal on the
backplane, driven by the system host. Platforms may implement
this signal as a radial signal from the Hot Swap Controller to
further control the electrical connection process. Platforms that do
this must OR the system host’s reset signal with the slot specific
signal to maintain the bussed signal’s function.