Anyone help me with a simple de-bounce idea?
Moskog
Posts: 556
Hello, I have a push button in a simple counter, counting one number upwards each time button is pressed and starting from 1 again after reaching 5.
Like this:
Like this:
number := 1
repeat
if ina[button] == %0
number := (number + 1)
if number == 6
number := 1
waitcnt(clkfreq/100 + cnt)
But my problem is de-bounching and I would appreciate if anyone know a simple solution and will help!
Comments
Actually, what I think is best is to first wait to detect the key down, then wait for the key to go up, and then wait a while after that for the bouncing to go away...
Your waitcnt should be indented. Like so:
number := 1 repeat if ina[button] == %0 number := (number + 1) if number == 6 number := 1 waitcnt(clkfreq/100 + cnt)Bruce
It counts seconds, and performs the debounce on the 5 buttons.
Massimo
edit: it runs on a separate cog, stores the keypress and returns the reading in the main code when asked to.
After reading the button you should "clear" it.
CON onesec = 80_000_000 VAR long timer_stack[40] long seconds long switch, rilasciato PUB start cognew(conta,@timer_stack) pri conta|previous dira[16..20]~ seconds:=0 rilasciato:=0 switch:=0 ' repeat ' waitcnt(cnt+clkfreq) ' seconds++ previous:=cnt+clkfreq repeat if (cnt-previous)>0 seconds:=seconds+1 previous:=previous+clkfreq debounce pri debounce|button if switch== 0 button := (!ina[16..20])&%11111 if (button==0) if rilasciato > 0 rilasciato :=0 if button>0 if rilasciato ==0 waitcnt(clkfreq/100+cnt) if button == (!ina[16..20])&%11111 switch:=button rilasciato:=1 pub bottoni return switch pub clear_bottoni switch:=0 pub tempo return secondsAdditionally, you may want to have the routine after waiting for bounce to settle, make an additional delay and retest as a "Yes, the switch was really pushed" to separate accidental from deliberate presses of the switch.
pub debounce (pin, state, ms) | t, db '' Returns True if pin is held in state (0 or 1) for ms milliseconds dira[pin] := 0 ' make pin an input db := 0 ' clear debounce counter t := cnt repeat ms if (ina[pin] == state) ' if button pressed db += 1 ' increment counter else ' else db := 0 ' reset counter waitcnt(t += clkfreq / 1_000) return (db == ms)The method always runs ms milliseconds. If you want an early exit, replace the else clause (db := 0) with quit.