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Altera_Forum's avatar
Altera_Forum
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16 years ago

synthesis of modul reacting of signal change

hello

i have ciclon 2 fpga module. I want to ask is it possible to be synthesed module which react on chenage of signal (not on positive or negativ edge )

using if (clk'event )

insted if (clk'event and clk = '1')

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    No, the synthesizer needs either a rising edge of a clock, or a falling edge. You can't use both.

    Second this should only be used on an actual clock. If you want to monitor changes on a signal, it would be better to sample it using a real clock and compare it with its previous value.
  • Altera_Forum's avatar
    Altera_Forum
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    It's not a good habit to use both posedge and negedge of one clock.