start0
do
if stop=1 then
out=low
else
out=low
delay 10
out=high
delay 10
end if
loop

start1
do
if stopkey=1 then
stop=1
do
delay 50
loop until stopkey=0
if startkey=1 then
stop=0
do
delay 50
loop until startkey=0
delay 50
loop

Main:
Do
If Button1 Then OutputStart
If Button2 Then OutputStop
Loop


Sub OutPutStart
PWM 1, 50, 50 ' Freq=50Hz, 1A=50%
End Sub

Sub OutputStop
PWM 1, STOP
End Sub

Main:
Do
If Button1 Then Flag=1
If Button2 Then Flag=0


If Flag=1 Then OutputStart
If Flag=0 Then OutputStop

Loop



Sub OutPutStart
PWM 1, 50, 50 ' Freq=50Hz, 1A=50%
End Sub

Sub OutputStop
PWM 1, STOP
End Sub

...
Case "U" 'door up
q$= "Answering Door Up"
DoorUpRequest
IntLightSetAuto
ExtLightSetAuto

... and the associated subs...


Sub DoorUpRequest
If (FlagTest(DoorUp)=0) And (FlagTest(DoorUpMoving)=0) Then 'if we are not already moving UP
Release
FlagSet DoorUpMoving
After DoorMovePeriod,DoorMoveTimer
Else
q$= "Ignored (flags)"
Endif
End Sub

Sub IntLightSetAuto
FlagRes IntLightON
FlagRes IntLightOFF
FlagSet IntLightAUTO
FlagRes ExtLightFLASH
End Sub

Sub ExtLightSetAuto
FlagRes ExtLightOR
If FlagTest(DoorDown) Then
FlagRes ExtLightONEnable
FlagSet ExtLightOFF
Else
FlagRes ExtLightOFF
FlagSet ExtLightONEnable
EndIf
End Sub


... and then in the main/service loop... just one, bit...

'process states
'door moving states
If FlagTest(DoorUpMoving) Then
Pin(DoorUp)=DoorActive
EndIf

' symbol declaration
symbol bStop = b0
symbol bOut = B.0
symbol bStopKey = pinB.1
symbol bStartKey = pinB.2

' task 0 : generate 50Hz square wave
' or do other real time stuff
start0:
do
if bStop=1 then
low bOut
else
low bOut
pause 10
high bOut
pause 10
end if
loop

' task 1 : completely unrelated check keys
' debounce (blocking) without affecting task 0
start1:
do
if bStopKey=1 then
bStop=1
do
pause 50
loop until bStopKey=0
end if

if bStartKey=1 then
bStop=0
do
pause 50
loop until bStartKey=0
end if
pause 50
loop

start0:
do
play music
loop

start1:
do
check_for_collisions
loop

start2:
do
read keyboard or game paddle
loop

start3:
do
process movements
update screen
loop