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AR# 7812

FPGA Express 3.x: Address lines unconnected when SRL16 components are instantiated (FPGA-CHECK-7)

Description

Keywords: Virtex, FPGA, Express, Foundation, SRL16, SRL16E, address, instantiate

Urgency: Standard

General Description:
When an SRL16 or SRL16E component is instantiated in a Virtex design in FPGA Express, the
following error will occur for any of the four address pins that are connected:

Warning: The net '/my_srl/addr<0>' has no load. (FPGA-CHECK-7)

If you open the schematic created by FPGA Express and push into the SRL instance, you will
see a large shift register that has no connections for the four address lines. These connections
will be left out of the final EDIF netlist.

解决方案

Static length shift registers can be inferred by FPGA Express 3.3. See (Xilinx Solution 5800)
for more information about how this is done.

However, if you need a dynamic length shift register, inference is not possible. The workaround
in this case would be the same as described in (Xilinx Solution 4588); create a schematic
representation of the SRL16 component and instantiate it as a black box.
AR# 7812
创建日期 10/04/1999
Last Updated 08/30/2001
状态 Archive
Type 综合文章