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Altera_Forum
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14 years ago

comparator with memory

Hello, I'm starting with vhdl, and i'm try to write any kind of comaprator with memory of the out signal. Can anyboidy help me.. Program have to check state of input from keypad (ps2) and chec...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

The OR chain you wrote is not correct; it will reduce in a

((li2) /= (li1)) and (li1 = X"7F")

condition, since you are logically ORing the 8bit codes of keys.

You should write:

... (li1 = X"21") OR (li1 = X"23") OR (li1 = X"24") OR ....