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Altera_Forum
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13 years ago

[D-TYPE flip-flop vhdl] a brief question about process

Hello guys, here is vhdl code from the lecture slide. I don't understand why the prof chose the put the output outside of the process. Just wondering, if the clock is slow, and it's not yet at fal...
Altera_Forum's avatar
Altera_Forum
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13 years ago

Regarding Qbar, you need to put it outside as it is, since otherwise the compiler creates a second register to invert Q into Qbar.

You can replace Qtemp with Q directly inside process and get rid of "Q <= Qtemp" which is outside process. In your case it is just wiring of Q to Qtemp but it will be rejected by compiler because you are not allowed to read output Q back. So Qtemp works as convenient intermediary.