case

mikea

I'm having a problem getting "case" to work in this code. i can see in the pst that it is seeing the pulses accurately. The compiler highlights the"<" just below the case and expects an expression term. I've tried this different ways with no luck. What am i doing wrong? -mike

  repeat
     waitpeq(%000, |< 2, 0) ' wait for Pin 2 to go low         '
     waitpeq(%100, |< 2, 0) 'Wait for Pin 2 to go high         '
     startpulsep:=cnt                                          '
     waitpeq(%000, |< 2, 0) ' wait for Pin 2 to go low         '
     endpulsep:=cnt                                            '    read  pulse width  from receiver
     waitpeq(%100, |< 2, 0) 'Wait for Pin 2 to go high         '
                                             '
     pulsewidthp:=endpulsep-startpulsep

     case pulsewidthp                  'test current pulsewidth value against the values below it
       <120000 and  <128000 : dead    'go to the dead method 
       >128000 :down                 'go to the down method
       <120000 :up                  'go to the up method

cavelamb

case X+Y 'Test X+Y
    10, 15: !outa[0] 'X+Y = 10 or 15? Toggle P0
    20..30: !outa[2] 'X+Y in 20 to 30? Toggle P2

Page 60, 61 of the manual.

Mike Green

That's not the proper syntax. Reread the Propeller Manual section on the CASE statement. For what you want, you'll need to use IF statements like:

IF pulsewidthp < 120000
   up
ELSEIF pulsewidthp > 128000
   down
ELSE
   dead

mikea

I see it now in the manual, if then else for comparing a number of different values. Thanks guys. -mike

cavelamb

or 0 .. 12000 for the case structure