DCM with Xilinx Spartan 3E and Precision

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.

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

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