Xilinx LogiCore PLB PCI Full Bridge - Manual (Page 52)

PLB PCI Full Bridge (v1.00a)
52 www.xilinx.com DS508 March 21, 2006
Product Specification
EARL
Y ACCESS
The constraints are also implemented automatically in the EDK tool flow with any tool option that
invokes bridge synthesis. In this flow, tcl-scripts generate the ucf-file constraints and place them in a
file in the OPB PCI Bridge directory of the project implementation directory. The ucf-file constraints are
then included in the ngc-file generated in the EDK tool flow. The user can check the ucf-file in the
implementation directory of the bridge directory to verify that the constraints are included. As noted
above, the user can include all constraints in the top-level ucf-file. When the constraints are included in
both the top-level ucf-file and the bridge ngc-file (via the bridge directory ucf-file), then the top-level
ucf-file overrides any conflicting constraints in the bridge ngc-file.
To remind the user that the following constraints must be included, PLATGEN will generate the
message:
The OPB PCI Bridge design requires design constraints to guarantee performance.
Please refer to the OPB IPIF/LogiCORE PCI64 v3.0 bridge design data sheet for
details.
Additional bridge specific constraints are required and an example ucf-file is provided in the EDK
pcores library. To remind the user that the additional bridge related constraints must be included in the
top-level ucf-file, PLATGEN will generate the message:
An example UCF is available for this core and must be modified for use in the
system. Please refer to the EDK Getting Started guide for the location of this
file.
The constraints that the LogiCORE PCI64 v3.0 core require to meet PCI specifications are shown below.
All io buffers must have IOB=TRUE
IOSTANDARD must explicitly list PCI33_3. Both BYPASS IOBDELAY=BOTH must be included for all
PIC ports, as shown below.
NET "PCI_AD(*)" IOSTANDARD=PCI33_3;
NET "PCI_CBE(*)" IOSTANDARD=PCI33_3;
NET "PCI_PAR" IOSTANDARD=PCI33_3;
NET "PCI_FRAME_N" IOSTANDARD=PCI33_3;
NET "PCI_TRDY_N" IOSTANDARD=PCI33_3;
NET "PCI_IRDY_N" IOSTANDARD=PCI33_3;
NET "PCI_STOP_N" IOSTANDARD=PCI33_3;
NET "PCI_DEVSEL_N" IOSTANDARD=PCI33_3;
NET "PCI_PERR_N" IOSTANDARD=PCI33_3;
NET "PCI_SERR_N" IOSTANDARD=PCI33_3;
#Include next 2 if routed to pins
NET "IDSEL" IOSTANDARD=PCI33_3;
NET "GNT_N" IOSTANDARD=PCI33_3;
NET "PCI_AD(*)" BYPASS;
NET "PCI_CBE(*)" BYPASS;
NET "PCI_PAR" BYPASS;
NET "PCI_FRAME_N" BYPASS;
NET "PCI_TRDY_N" BYPASS;
NET "PCI_IRDY_N" BYPASS;
NET "PCI_STOP_N" BYPASS;
NET "PCI_DEVSEL_N" BYPASS;
NET "PCI_PERR_N" BYPASS;
NET "PCI_SERR_N" BYPASS;
#