In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Zoot wrote:

e.g.


[code]
:startdebounceroutine
CLR buttonCount
:again
MOV buttonPrev, buttonState ' load previous button state
MOV W, #0   ' presume active low, but make 1 if button pressed
SB ButtonPin
   MOV W, #1
MOV buttonState, W
XOR W, buttonPrev
SZ
   CLR buttonCount ' if unstable, reset debounce count
JNZ, @:again  ' if it's unstable, repeat
   INC buttonCount ' how many times stable
   CJB buttonCount, #100, @:again  ' adjust depending on clock frequency, switch noise, etc. This is 500us debounce or so at 20mhz, not much

' now the current debounced state of the button is in buttonState....
JNB buttonState.0, @:nolight

:light
  SETB LedPin
  MOV tmpB1, #200 ' these two numbers depend on clock speed, easier in an ISR, really
  MOV tmpB2, #200

:pauseloop
  TEST tmpB2
  JNZ, :dec
    TEST tmpB1
    JZ, @:nolight
:dec
  SUB tmpB1, #1
  SUBB tmpB2, /C
  JMP @:pauseloop

:nolight
   CLRB LedPin

:done

[/code]

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