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AR# 32727

Endpoint Block Plus Wrapper v1.11 for PCI Express - MAP fails to complete due to predictable IP placement constraints

Description


Known Issue: v1.11, v1.10.1, v1.10

When implementing, MAP abruptly ends and no NCD file is created. A message similar to the following appears in the progress window:

"Phase 4.37 Local Placement Optimization
Predictable IP: No comp with name
ep/BU2/U0/pcie_ep0/pcie_blk_if/ll_bridge/tx_bridge/tx_bridge/llk_tlp_halt
[present in XIL_PAR_PATH attribute] found"

解决方案


NOTE: With the release of 11.2, users should be aware that unless the default instance name of "ep" is used as described below, the predictable IP constraints will not be used. This might have negative impacts on timing closure.

With the release of 11.1, the Block Plus Core uses predictable IP constraints to assist in timing closure. This problem is due to MAP not recognizing the constraint if the user does not use the default instance name of "ep" when instantiating the core.

For example, the following will work:

endpoint_blk_plus_v1_10_1 ep (

// SYS Interface
.sys_clk_p(cor_sys_clk_p),
.sys_clk_n(cor_sys_clk_n),

// PCI-Express Interface
.pci_exp_txn(cor_pci_exp_txn),
.pci_exp_txp(cor_pci_exp_txp),
.pci_exp_rxn(cor_pci_exp_rxn),
.pci_exp_rxp(cor_pci_exp_rxp),

.sys_reset_n(cor_sys_reset_n)
);


but this would fail:

endpoint_blk_plus_v1_10_1 custom_name (

// SYS Interface
.sys_clk_p(cor_sys_clk_p),
.sys_clk_n(cor_sys_clk_n),

// PCI-Express Interface
.pci_exp_txn(cor_pci_exp_txn),
.pci_exp_txp(cor_pci_exp_txp),
.pci_exp_rxn(cor_pci_exp_rxn),
.pci_exp_rxp(cor_pci_exp_rxp),

.sys_reset_n(cor_sys_reset_n)
);


This example fails to MAP correctly because the name of the instance has changed to something other than the default "ep".

To work around this issue in 11.1, use the default instance name of "ep", or use the following environment variable to force MAP to ignore the constraint:

XIL_PAR_NO_PREDICTABLE_IP = 1

ISE 11.2 will not have this problem because the software ignores invalid predictable IP constraints if the instance name does not match "ep" as described above. The v1.12 Block Plus Core, released in ISE 11.3, will be modified to use wildcards instead of "ep", so that custom instance names can be used. ISE 11.3 will be enhanced to support these wildcards.

Revision History
06/24/2009 - Added "Note" about 11.2 release.
05/28/2009 - Updated comment about 11.2.
05/20/2009 - Initial Release.
AR# 32727
创建日期 05/20/2009
Last Updated 12/15/2012
状态 Active
Type 综合文章
IP
  • Endpoint Block Plus Wrapper for PCI Express