DC synthesis Unconnected input

[dftrtl]

In DC synthesis what will happen to floating inputs.
Does it tie off them to tielow ?

 

[lohi21]

DC does not automatically tie inputs or outputs. you will have to either get that info from RTL or use command to tie unconnected pins.

 

[sun_ray]

dftrtl

DC automatically does not tie a floating input to high/low. But if the input is not at all used, there is a high chance that it will remove the input.

Regards

 

[englishdogg]

Agreed that it will not automatically tie a floating input; but to my knowledge it will not remove it as well.
Usually it leaves it in the verilog with SYNOPSYS_UNCONNECTED_ also I do not think it should play with the module definitions

Pls let me know if my understanding is correct.

 

[sakthikumaran87]

From my knowledge the port input cannot be removed as well as not tied to any value. Lint toll or synthesis tool generally use to theow warnings on unconnected input/output port. If the input is just declared and not logically used, then this warning can be waived. else proper care should be given to tie the input/feed the input.