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Lucent Technologies Inc.
Preliminary Data Sheet
August 2000
ORCA Series 4 FPGAs
FPGA States of Operation
(continued)
Reconfiguration
To reconfigure the FPGA when the device is operating
in the system, a low pulse is input into
PRGM or a pro-
gram command is sent to the system bus
. The configura-
tion data in the FPGA is cleared, and the I/Os not used
for configuration are 3-stated. The FPGA then samples
the mode select inputs and begins reconfiguration.
When reconfiguration is complete, DONE is released,
allowing it to be pulled high.
Partial Reconfiguration
All ORCAdevice families have been designed to allow
a partial reconfiguration of the FPGA at any time. This
is done by setting a bit stream option in the previous
configuration sequence that tells the FPGA to not reset
all of the configuration RAM during a reconfiguration.
Then only the configuration frames that are to be modi-
fied need to be rewritten, thereby reducing the configu-
ration time.
Other bit stream options are also available that allow
one portion of the FPGA to remain in operation while a
partial reconfiguration is being done. If this is done, the
user must be careful to not cause contention between
the two configurations (the bit stream resident in the
FPGA and the partial reconfiguration bit stream) as the
second reconfiguration bit stream is being loaded.
Other Configuration Options
There are many other configuration options available to
the user that can be set during bit stream generation in
ORCA Foundry. These include options to enable
boundary-scan and/or the MPI and/or the programma-
ble PLL blocks, readback options, and options to con-
trol and use the internal oscillator after configuration.
Other useful options that affect the next configuration
(not the current configuration process) include options
to disable the global set/reset during configuration, dis-
able the 3-state of I/Os during configuration, and dis-
able the reset of internal RAMs during configuration to
allow for partial configurations (see above). For more
information on how to set these and other configuration
options, please see the ORCA Foundry documenta-
tion.
5-5759(F)
Figure 36. Serial Configuration Data Format—Autoincrement Mode
5-5760(F)
Figure 37. Serial Configuration Data Format—Explicit Mode
CONFIGURATION DATA
CONFIGURATION DATA
1 0
0 1
0 1
PREAMBLE LENGTH
ID FRAME
CONFIGURATION
DATA FRAME 1
CONFIGURATION
DATA FRAME 2
POSTAMBLE
CONFIGURATION HEADER
0 0
0 0
COUNT
PREAMBLECOUNT
ID FRAME
CONFIGURATION
DATA FRAME 1
CONFIGURATION
DATA FRAME 2
POSTAMBLE
CONFIGURATION HEADER
ADDRESS
FRAME 1
ADDRESS
FRAME 2
0 0
CONFIGURATION DATA
CONFIGURATION DATA
1 0
0 1
0 1
0 0
0 0
0 0