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I am interfacing a VGA monitor with Spartan 3e kit. I have a problem in the code and I'm getting many warnings, as shown below.

Could anyone explain the warnings?

    WARNING:Xst:1780 - Signal <reg_led> is never used or assigned. This unconnected signal will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <v_count_reg_3> (without init value) has a constant value of 0 in block <vsync_unit>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <v_count_reg_2> (without init value) has a constant value of 0 in block <vsync_unit>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <v_count_reg_1> (without init value) has a constant value  of 0 in block <vsync_unit>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <v_count_reg_0> (without init value) has a constant value of 0 in block <vsync_unit>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <mod2_reg> (without init value) has a constant value of 0 in block <vsync_unit>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1710 - FF/Latch <h_sync_reg> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_sync_reg> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_9> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_8> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_7> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_6> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_5> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_4> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_3> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_2> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_1> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <h_count_reg_0> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_9> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_8> (without init  value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_7> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
   WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_6> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
    WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_5> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
     WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_4> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
     WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_3> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
      WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_1> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
       WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_0> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
       WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <mod2_reg> (without init value) has a constant value of 0 in block <vga_sync>. This FF/Latch will be trimmed during the optimization process.
       WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <v_count_reg_2> (without    init value) has a constant value of 0 in block <vga_sync>. This FF/Latch wiProcess "Synthesize - XST" completed successfully
       WARNING:Pack:1543 - The register rgb_reg_1_3 has the property IOB=TRUE, but was
       not packed into the input side of an I/O component. The IFF1 BEL site already
      contains the register symbol "rgb_reg_1_1".
       The IFF2 BEL site already contains the register symbol "rgb_reg_1_2".
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  • \$\begingroup\$ KIt am using is spartan 3e xc3s1200e 4fg320 and i have googled about tese warnings but didn't got any info.. \$\endgroup\$ – Red1 Oct 5 '13 at 19:53
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    \$\begingroup\$ There isn't much we can do unless you show us the code that generated these warnings. \$\endgroup\$ – Dave Tweed Oct 5 '13 at 20:14
  • \$\begingroup\$ sir these are my codes for spartan 3e xc3s1200e pacakage is 4fg30 could u please correct this if u could dropbox link for my .v,.ucf code and reference manual of spartan 3e kit just see them \$\endgroup\$ – Red1 Oct 5 '13 at 20:20
  • \$\begingroup\$ @Red1 Dont use dropbox, put it in your question. Dont ask the same question again, improve this one. \$\endgroup\$ – Kortuk Oct 14 '13 at 14:27
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The warnings are pretty self-explanatory. The reg_led signal is not connected to an FPGA output pin so the tools have deleted it. It seems that the value in the v_count_reg never changes so the tools have deleted the unnecessary flip-flops. I suspect that you have not created the User Constraints File and connected the signals in your design to specific pins on the FPGA. If you have in fact created a UCF file, then run a simulation and figure out why v_count_reg doesn't ever change.

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  • \$\begingroup\$ i Have created a ucf file but iam using v_count_reg as an intermediate reg and i want to know that any problem if their are warnings in the code for hardware simulation \$\endgroup\$ – Red1 Oct 5 '13 at 20:06
  • \$\begingroup\$ The tools are telling you that you created a register but its value never changes. If that's the behavior you want in your design then you can ignore the warning. However, this is probably not what you intended and it will almost certainly create a problem in the hardware. You must create a proper testbench and simulate your design to resolve this issue. \$\endgroup\$ – Joe Hass Oct 5 '13 at 20:08
  • \$\begingroup\$ sir these are my codes for spartan 3e xc3sc1200e pacakage is 4fg30 could u please correct this if u could dropbox link for my .v,.ucf code and reference manual of spartan 3e kit just see them \$\endgroup\$ – Red1 Oct 5 '13 at 20:18

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