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Visitor 2016pev5432
Visitor
253 Views
Registered: ‎04-21-2019

Error in Implementation of design

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Ihave created my own adder and multipliers, which work fine and are imlpemented indivdually.

But when they are instances in other module this error shows up when implemenating.

Please help

 

Place Design

[Place 30-494] The design is empty
Resolution: Check if opt_design has removed all the leaf cells of your design. Check whether you have instantiated and connected all of the top level ports.

[Common 17-69] Command failed: Placer could not place all instances

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Scholar u4223374
Scholar
244 Views
Registered: ‎04-26-2015

Re: Error in Implementation of design

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Are all of the inputs and outputs from your design actually connected to something (eg. I/O pins)? If not, Vivado will remove them (because there's no point including an output that doesn't drive anything, and no point including an input that has a constant value). This can very rapidly result in an empty design.

4 Replies
Scholar u4223374
Scholar
245 Views
Registered: ‎04-26-2015

Re: Error in Implementation of design

Jump to solution

Are all of the inputs and outputs from your design actually connected to something (eg. I/O pins)? If not, Vivado will remove them (because there's no point including an output that doesn't drive anything, and no point including an input that has a constant value). This can very rapidly result in an empty design.

Visitor 2016pev5432
Visitor
242 Views
Registered: ‎04-21-2019

Re: Error in Implementation of design

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My top module has juat one input "clk" and no output, I have created a register to save output.

Means should I still connect them to some port?

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Scholar richardhead
Scholar
237 Views
Registered: ‎08-01-2012

Re: Error in Implementation of design

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With no output pins connected,  an empty chip functions exactly the same as the most complicated circuit with no outputs.  Vivado will always reduce logic equations to reduce resource usage,  and unconnected outputs is the easiest savings to make

Scholar u4223374
Scholar
198 Views
Registered: ‎04-26-2015

Re: Error in Implementation of design

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As @richardhead has said, with no input/output, there is no way that you can distinguish between a chip running your code and a blank chip. Vivado knows that, and so it just removes all your logic.

 

There are a couple of fixes, but the obvious one is to connect all module inputs and outputs to I/O pins.

 

 

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