aUCBLogo Demos and Tests / steppermotor2

be steppermotor2
   adr=888
   state=0
   steps=64
   speed=50000
   print [If a stepper motor is connected be bit 0..3 of the parallel port]
   print [then  + F2 F3 F4 \  F5 F6 F7 -  are the driving keys]
   print [ESC stops]
   running=true
   while [running]
   [   ch=readChar
      if ch==char 27 [running=false]
      if ch=="+ [drive steps]
      if ch=="- [drive -steps]
      if ch==char 255
      [   ch=readCharExt
         case ch
         [   [WXK_F1 drive -steps]
            [WXK_F2 drive lshift -steps -2]
            [WXK_F3 drive lshift -steps -4]
            [WXK_F4 drive lshift -steps -6]
            [WXK_F5 drive lshift steps -6]
            [WXK_F6 drive lshift steps -4]
            [WXK_F7 drive lshift steps -2]
            [WXK_F8 drive steps]
         ]
      ]
   ]
   PortOut adr 255

   be drive steps
      ifelse steps < 0
      [   drivebackward -steps
      ][   driveforward steps
      ]
   end

   be driveforward steps
      if steps==0 [stop]
      state=state+1
   ;   bits=BitNot UInt8 lshift 1 BitAnd state 3
      case mod state 4
      [   [0 bits=0]
         [1 bits=1]
         [2 bits=3]
         [3 bits=2]
      ]
      bits=UInt8 bits
      (pr steps IntForm bits 4 2)
      PortOut adr BitNot bits
      waituS speed
      driveforward steps-1
   end

   be drivebackward steps
      if steps==0 [stop]
      state=state-1
   ;   bits=abs BitNot UInt8 lshift 1 BitAnd state 3
      case mod state 4
      [   [0 bits=0]
         [1 bits=1]
         [2 bits=3]
         [3 bits=2]
      ]
      bits=UInt8 bits
      (pr steps IntForm bits 4 2)
      PortOut adr BitNot bits
      waituS speed
      drivebackward steps-1
   end
end