Logic contention(s) detected on net

[Ashkan2200]

hi
i'm new with proteus and have 74191 and 74154 ICs and i want to connect 74191 output to 74154 input but i get 4 errors about "Logic contention(s) detected on net "
please help me

Here us a Picture:

 

[BradtheRad]

The simulator may have trouble finding initial output states of your second IC (although you would not get such an error in hardware). Try experimenting with pullup/down resistors at the inputs.

Also try putting led's on the outputs of the first IC. This will tell you if the simulator can create stable states at powerup, then behave in the expected manner as it continues to run.

 

[Ashkan2200]

hi
i did what you said but i wasn't able to fix it , pls can i send you the file and you take a look at it?

 

[BigBoss]

OUT/INP directions may be erroneous.
Just a guess

 

[BradtheRad]

hi
i did what you said but i wasn't able to fix it , pls can i send you the file and you take a look at it?

Sorry I have no experience with Proteus. All I can recommend is for you to get each IC working by itself alone. Later you can connect them.