Specifications
Dynamic Board Reconfiguration
XAPP938 (v1.0) March 28, 2007 www.xilinx.com 5
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Virtex-4, Virtex-II Pro, Virtex-E (v5) Core for PCI-X Designs
The configuration file parameters used as part of a reconfiguration design are shown in Tabl e 5.
These bits are found in the 512-bit configuration vector input to the LogiCORE for PCI-X
designs.
Setting BM_DETECT_DIS (v4 and v6 core) or bit 504 (v5 core) does not disable the ability of
the core to recognize the bus mode. The RTR output is asserted to the user application if the
bitstream loaded is in the wrong mode for the bus. When using two bitstreams, one for PCI
operation and one for PCI-X operation, BM_DETECT_DIS or bit 504 must be set to 1. The
“Design Setup” section discusses these signals.
Board Setup
To reconfigure bitstreams, certain board design requirements are necessary. This application
note uses the setup on the ML455 board. This board meets the basic requirements, including
an FPGA that supports the core for PCI-X, a CPLD for the dynamic reconfiguration design, and
a method of storing two bitstreams. Figure 3 shows the connections between the Virtex-4
FPGA, CPLD, and Platform Flash on the ML455 board.
Table 5: Configuration Vector Parameters
Parameter Bit Description
Bus Mode Detect Disable 504
Setting this bit to 1 forces the LogiCORE for PCI-X to start
in the mode set by bit 505.
Bus Mode Manual as PCI 505
If bit 504 is set to 1, setting this bit to 1 forces the core to
operate in PCI mode. Setting this bit to 0 forces the core to
operate in PCI-X mode. If bit 504 is not set, then this bit has
no effect on the core.
Bus Width Detect Disable 502
Setting this bit to 1 forces the core to ignore the bus width
initialization pattern and use the width indicated by the Bus
Width Manual as 32 bit or bit 503 instead.
Bus Width Manual as 32-bit 503
If bit 502 is set to 1, setting this bit to 1 forces the core to
assume it is plugged into a 32-bit bus. Setting this bit to 0
forces the core to assume it is plugged into a 64-bit
capable bus. If bit 502 is not set, then this bit has no effect
on the core.