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Altera_Forum
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16 years ago

implementing a mux using high impedances

I have many streaming input ports that I want to connect to a single streaming output port. Rather than using a VHDL case or lengthy ifels statement, I was wondering if I could get tricky with...
Altera_Forum's avatar
Altera_Forum
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16 years ago

Please read page 6-46 of the coding guidelines:

http://www.altera.com/literature/hb/qts/qts_qii51007.pdf

In addition to kaz and FvM's comments, you really should avoid internal tri-states whenever possible. It's truly a luxury for us that the tools even handle them at all. There is no such thing as an internal tri-state in FPGAs. All you are doing is forcing the compiler to figure out a muxing scheme for you and it may not be as efficient as you doing it yourself. And this sort of coding really doesn't fly in the ASIC design world.

Jake