-- Vers. 1.3 for Director, 2 May 2000
-- requires DirectComm Xtra from http://www.directxtras.com
-- Do not delete! Movie Script! Nothing will work!!
-- Director for Macintosh or Windows EZ I/O movie script
-- ===========================================================================
-- © 1997 The Regents of the University of Michigan All rights reserved.
-- Developed at the University of Michigan School of Art and Design 
-- by Michael Rodemer and Ed Bennett
-- ===========================================================================
-- the following gets Director ready to do serial communication with the microcontroller
-- on the interface board. It MUST be called before any of the other scripts associated
-- with the board will work!
-- modem port recommended; otherwise, turn off appleTalk on printer port
-- Version 1.2 fixes the problem of Director not waiting for the serial port to return a value
-- Version 1.3 fixes a problem with the DirectComm xtra needing more parameters to be set in Windows

on startMovie
  global port
  -- init serial port
  set port = New ( Xtra "DirectCommunication", 0, "lpt1", 1600,1600) -- "COM1" selects modem port, "LPT1" selects printer port
  -- if you decided to use the printer port, make sure AppleTalk isn't using it
  SetCommBaudRate (port, 57600 ) -- sets port to 57600 baud
  SetCommStopBits (port, 0 ) -- sets port to 1 stop bit
  setCommDataBits(port, 8)
  setCommParity(port, 0)
  setCommFlowControl(port, 0)
  put port -- this is a bit of optional feedback
end
-- ===========================================================================
-- "numtochar()" is used often: it changes a number into a character,
-- which is a convenient way to represent a number between 0 and 255, 
-- for transmitting it to the board

-- ===========================================================================
-- A2D will read a voltage and return its value, 
-- expressed as a number between 0 and 255

on A2D lineNo --valid line numbers are 1-8
  global port
  FlushComm(port) -- this clears out the receive buffer
  put numtochar((lineNo-1)) into lineNo -- internally, the chip starts numbering lines at zero
  WriteComm(port, "A" & lineNo) -- sends command to board
  put void into state
  startTimer
  repeat while (the length of state <> 1)
    put ReadComm(port)into state
    if the timer>300 then
      alert "There is a problem with the serial communication!"
      exit repeat
    end if
  end repeat-- this causes the program to wait for serial transmission to complete
  return chartonum(state) -- returns result from board
end 

-- ===========================================================================
-- writePort will cause a pattern of ons and offs on lines Digital Out 1 through 8 on the board
-- depending on the value of the variable "state"

on writePort state -- valid values for state are 0-255
  global port
  put numtochar(state) into state 
  WriteComm(port, "W" & state)
end 

-- =============================================================================
-- writeLine turns a single line on or off, "1" being "on," "0" being "off"
-- EZ I/O offers ten lines of digital output
on writeLine lineNo, onOff  -- valid line numbers are 1 through 10
  global port
  put numtochar((lineNo-1)) into lineNo -- internally, the chip starts numbering lines at zero
  put numtochar(onOff) into onOff
  WriteComm(port, "w" & lineNo & onOff)
end

-- ===========================================================================
-- readLine returns a ¯ or 1 to indicate the state of a single line,
-- with "1" being "high" and "0" being "low"
-- the default state, when a line has nothing switched, is "1"
-- (see instructions for using digital input)

on readLine lineNo  -- valid line numbers are 1 through 10
  global port
  FlushComm(port) -- this clears out the receive buffer
  put numtochar((lineNo-1)) into lineNo
  WriteComm(port, "r" & lineNo)
  put void into state
  startTimer
  repeat while (the length of state <> 1)
    put ReadComm(port)into state
    if the timer>300 then
      alert "There is a problem with the serial communication!"
      exit repeat
    end if
  end repeat-- this causes the program to wait for serial transmission to complete
  return chartonum(state) -- returns result from board
end

-- ===========================================================================
-- readPort returns a value between 0 and 255 for the 8-line port
-- comprised of lines Digital Input 1 through 8 on the board
-- the default state, when no lines are switched, is "255"
-- (see instructions for using digital input)

on readPort      
  global port
  FlushComm(port) -- this clears out the receive buffer
  WriteComm(port, "R")
  put void into state
  startTimer
  repeat while (the length of state <> 1)
    put ReadComm(port)into state
    if the timer>300 then
      alert "There is a problem with the serial communication!"
      exit repeat
    end if
  end repeat-- this causes the program to wait for serial transmission to complete
  return chartonum(state) -- returns result from board
end 

-- ===========================================================================
-- PWM turns a line on and off rapidly (more than 18,000 times a second),
-- varying the ratio of the time the line is off to the time it is on.
-- Valid input values are from 0 (always off) to 1023 (always on)

on PWM lineNo, onTime -- valid line numbers are 1 or 2
  global port
  put numtochar(lineNo) into lineNo
  -- the following code makes two 8-bit numbers
  -- out of the 10-bit number (0-1023) passed to PWM as an argument,
  -- passing two characters to the board one after the other
  
  put 0 into temp
  if (onTime-512>=0) then
    put (temp+2) into temp
    put (onTime-512) into onTime
  end if
  if (onTime-256>=0) then
    put (temp+1) into temp
    put (onTime-256) into onTime
  end if
  put temp into hiBite
  put onTime into loBite
  put numtochar(hibite) into hibite
  put numtochar(lobite) into lobite
  WriteComm(port, "P" & lineNo & hiBite & loBite)
end

-- ===========================================================================
-- this frees up the serial link from the desktop computer before quitting Director

on stopMovie
  global port
  set port = void
end
-- ===========================================================================