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Altera_Forum
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15 years ago

Problem with MAX II EPM240T100

Hello people, I tell you my serious problem I have programmed a state machine in VHDL. This state machine works with an external clock´s pulses. Simulation is OK. When I see waveforms in...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

You have to synchronise asynchronous external inputs with a 2-stage register chain before letting it interact with the state machine.

You may want to look up 'metastability' to learn what can/will happen otherwise.