
Device Architecture
2-144
Revision 4
Hot-Swap Support
Hot-swapping (also called hot plugging) is the operation of hot insertion or hot removal of a card in (or
from) a powered-up system. The levels of hot-swap support and examples of related applications are
described in
Table 2-74. The I/Os also need to be configured in hot insertion mode if hot plugging
compliance is required.
Table 2-74 Levels of Hot-Swap Support
Hot
Swapping
Level
Description
Power
Applied
to Device Bus State
Card
Ground
Connection
Device
Circuitry
Connected
to Bus Pins
Example of
Application with
Cards that Contain
Fusion Devices
Compliance of
Fusion Devices
1
Cold-swap
No
–
System and card with
Microsemi FPGA chip
are powered down,
then card gets
plugged into system,
then power supplies
are turned on for
system but not for
FPGA on card.
Compliant I/Os
can but do not
have to be set to
hot insertion
mode.
2
Hot-swap
while reset
Yes
Held in
reset state
Must be made
and
maintained for
1 ms before,
during, and
after insertion/
removal
–
In PCI hot plug
specification, reset
control circuitry
isolates the card
busses until the card
supplies are at their
nominal operating
levels and stable.
Compliant I/Os
can but do not
have to be set to
hot insertion
mode.
3
Hot-swap
while bus
idle
Yes
Held idle
(no ongoing
I/O
processes
during
insertion/re
moval)
Same as
Level 2
Must remain
glitch-free
during
power-up or
power-down
Board bus shared
with card bus is
"frozen," and there is
no toggling activity on
bus. It is critical that
the logic states set on
the bus signal do not
get disturbed during
card
insertion/removal.
Compliant with
cards with two
levels of staging.
I/Os have to be
set to hot
insertion mode.
4
Hot-swap on
an active
bus
Yes
Bus may
have active
I/O
processes
ongoing,
but device
being
inserted or
removed
must be
idle.
Same as
Level 2
Same as
Level 3
There is activity on
the system bus, and it
is critical that the logic
states set on the bus
signal do not get
disturbed during card
insertion/removal.
Compliant with
cards with two
levels of staging.
I/Os have to be
set to hot
insertion mode.