DCM with Xilinx Spartan 3E and Precision

Hello everyone,

I would like to use an DCM in a Xilinx Spartan 3E device. The synthesis is done with Mentor Graphics Precision. So I created a verilog file with verilog, but when I run synthesis, I get the error message:

# Error: [216]: Unable to resolve reference to an Instance: DCM_SP_INST of Cell work.DCM_SP. # Error: Found unresolved black-boxes in the design, please fix the previous error messages before continuing

It seems to me that Precision does not recognize Xilinx' DCM for Spartan devices.

Do You have any ideas?

Markus Fras

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Markus Fras
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Is the DCM_SP_INST something that was generated by the Xilinx Architecture Wizard? The Software Manual does not show a DCM_SP_INST primitive for the Spartan-3E.

You would need to include the black box Verilog file generated by the Architecture wizard in your project.

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I haven't worked with Spartan devices, and I don't use Verilog, but I've had problems with instantiating Xilinx primitives in VHDL without declaring them first, i.e. I get the same error message as you do when I just instantiate e.g. a BUFG out of the work library, without declaring it first.

The same applies in designs where I use the PicoBlaze... in the HDL for the PicoBlaze, there are flipflops, shift registers and such instantiated without being declared first, and I could never get that synthesized with Precision at first.

What I then did was add the source code for the UNISIM-library to my synthesis project (in $XILINX/vhdl/src/unisims/unisim_VCOMP.vhd). Inside this file are declarations for all Xilinx primitives, including the DSP_SP. Just including this in the synthesis fixed it for me.

HTH, Sean

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Reply to
Sean Durkin

Hello Sean,

thank You for Your help. Unfortunately, including the UNISIM source did not cure the problem. I tried the verilog and the VHDL version.

Finally, I upgraded to the latest version of Precision (2006a3.24), which now knows the DCM_SP. I can compile the design normally, without any changes now.

Best Regards,

Markus Fras

Sean Durk>> It seems to me that Precision does not recognize Xilinx' DCM for Spartan

Reply to
Markus Fras

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