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Altera_Forum
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11 years ago

Error (12014): Net "a", which fans out to "a", cannot be assigned more than one value

I'm designing a relatively simple circuit. Using two 4 to 2 encoders to realize an 8 to 3 encoder. Only been learning VHDL the last month. I don't know what this error means. I've done similar circui...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

The message is clear.

You can't drive a node from more than one source by direct wiring. You are driving (a) and (b) by two instants as outputs. If one is driving it high and the other low what is the result?

This is fundamental rule whether the drive is through assignments or instantiations. If you have to, then you need to decide a priority logic onto that node rather than direct wiring. (for io you can also use Z buffer)