Actel Fusion Mixed-Signal FPGAs
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 2-71. The I/Os also need to be configured in hot insertion mode
if hot plugging compliance is required.
Table 2-71 • Levels of Hot-Swap Support
Device
Example of
Hot
Power
Card
Circuitry
Application with
Swapping
Level
Applied
Ground
Connected Cards that Contain Compliance of
Description to Device Bus State Connection to Bus Pins
Fusion Devices
Fusion Devices
1
2
3
Cold-swap
No
Yes
Yes
–
–
–
System and card
with Actel FPGA chip can but do not
are powered down, have to be set to
Compliant I/Os
then card gets
hot insertion
plugged into system, mode.
then power supplies
are turned on for
system but not for
FPGA on card.
Hot-swap
while reset
Held in
Must be
–
In PCI hot plug
specification, reset can but do not
Compliant I/Os
reset state made and
maintained
for 1 ms
control circuitry
isolates the card
busses until the card mode.
supplies are at their
nominal operating
have to be set to
hot insertion
before,
during, and
after
insertion/
removal
levels and stable.
Hot-swap
while bus
idle
Held idle Same as Level Must
(no
ongoing
I/O
Board bus shared
with card bus is
Compliant with
cards with two
2
remain
glitch-free "frozen," and there levels of
during is no toggling staging. I/Os
processes
during
insertion/re
moval)
power-up activity on bus. It is have to be set to
or power- critical that the logic hot insertion
down
states set on the bus mode.
signal do not get
disturbed during
card
insertion/removal.
4
Hot-swap
on an active
bus
Yes
Bus may
have active 2
I/O
Same as Level Same as
Level 3
There is activity on Compliant with
the system bus, and cards with two
it is critical that the levels of
processes
ongoing,
but device
being
logic states set on
the bus signal do not have to be set to
get disturbed during hot insertion
staging. I/Os
card
mode.
inserted or
removed
must be
idle.
insertion/removal.
Preliminary v1.7
2-139
ACTEL [ Actel Corporation ]
