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Altera_Forum's avatar
Altera_Forum
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9 years ago

pulse counting

Hello, I'd like to code a pulse counter : after X pulses from a signal, another signal toggles (I choose 4 in my example). I wrote this piece of code, and the behavior is not as i expected...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
9 years ago

Then just do a rising edge detection circuit on the pulse, and count 4 of them.

Rising edge detect compars the current value with the last value: 


process(clk)
begin
  if rising_edge(clk) then
    pulse_r <= pulse;
    if pulse_r = '0' and pulse = '1' then
      toggle_cnt <= toggle_cnt + 1;
    end if;
    if toggle_cnt = 3 then
      toggle_cnt <= 0;
      toggle <= not toggle;
    end if;
  end if;
end process;