Python Stepper Script for UL2003 driver triggered by GPIO pins defined at line 76

focus.py

#!/usr/bin/python
#--------------------------------------
#    ___  ___  _ ____          
#   / _ \/ _ \(_) __/__  __ __ 
#  / , _/ ___/ /\ \/ _ \/ // / 
# /_/|_/_/  /_/___/ .__/\_, /  
#                /_/   /___/   
#
#    Stepper Motor Test
#
# A simple script to control
# a stepper motor.
#
# Author : Matt Hawkins
# Date   : 28/09/2015
#
# http://www.raspberrypi-spy.co.uk/
#
#--------------------------------------

# Import required libraries
import sys
import time
import RPi.GPIO as GPIO
import os
import atexit
import signal

StepCounter = 0
totalStep = 0
LOG_FILE="/var/log/focus_max.log"
LOG_FILE2="/var/log/focus_curr.log"

if os.path.isfile(LOG_FILE):
        with open(LOG_FILE, 'r') as l:
                last = None
                for line in (line for line in l if line.rstrip('\n')):
                        last = line
                maxposition=int(last)
else:
    maxposition=50000

if os.path.isfile(LOG_FILE2):
        with open(LOG_FILE2, 'r') as l:
                last = None
                for line in (line for line in l if line.rstrip('\n')):
                        last = line
                currposition=int(last)
else:
    currposition=0
minposition=0

if len(sys.argv)<2:
  print >> sys.stdout,"\r\n Usage: focus <ms> <stepsize> OR focus set min (to set the zero point)"
  print >> sys.stdout,"\r\n <ms> can be a positive integer between 1 and 250"
  print >> sys.stdout," <stepsize> can be -2, -1, 1 or 2 (positive figure moves clockwise, negative anticlockwise)\r\n"
  print >> sys.stdout," eg: focus 10 1, focus 2 -2, focus 1 1, focus 250 1\r\n\r\n"
  sys.exit()

@atexit.register
def handleSIGTERM():
    print >> sys.stdout, str(currposition)
    print >> sys.stderr, "DONE"
    current = currposition
    f = open(LOG_FILE2,'a')
    f.write(str(current)+"\n")
    f.close()
    GPIO.cleanup()
signal.signal(signal.SIGTERM, handleSIGTERM)

# Use BCM GPIO references
# instead of physical pin numbers
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

# Define GPIO signals to use
StepPins = [17,25,23,24]

# Set all pins as output
for pin in StepPins:
  GPIO.setup(pin,GPIO.OUT)
  GPIO.output(pin, False)

# Define advanced sequence
# as shown in manufacturers datasheet
Seq = [[1,0,0,1],
       [1,0,0,0],
       [1,1,0,0],
       [0,1,0,0],
       [0,1,1,0],
       [0,0,1,0],
       [0,0,1,1],
       [0,0,0,1]]

StepCount = len(Seq)
if sys.argv[1] == "set":
  if sys.argv[2] == "min":
    currposition=0
    f = open(LOG_FILE2,'a')
    f.write(str(currposition)+"\n")
    f.close()
  else:
    f = open(LOG_FILE,'a')
    f.write(str(currposition)+"\n")
    f.close()
elif sys.argv[1] =="clear":
    f = open(LOG_FILE,'a')
    f.write(str(45000)+"\n")
    f.close()
    f = open(LOG_FILE2,'a')
    currposition=22500
    f.write(str(22500)+"\n")
    f.close()
else:
# Read wait time from command line
  if len(sys.argv)>1:
    WaitTime = int(sys.argv[1])/float(1000)
  else:
    WaitTime = 10/float(1000)
  StepDir = int(sys.argv[2])
  # Start main loop
  try:
    while True:
      if ((currposition<maxposition) or (currposition==maxposition and (currposition+StepDir<maxposition))) and currposition+StepDir>minposition:
        for pin in range(0, 4):
          xpin = StepPins[pin]
          if Seq[StepCounter][pin]!=0:
            GPIO.output(xpin, True)
          else:
            GPIO.output(xpin, False)
        StepCounter += StepDir
        totalStep += StepDir
        currposition += StepDir
        #print >> sys.stdout, str(currposition)+"\n"
        #print >> sys.stdout, str(StepCounter)+"|" + str(totalStep)+"\r\n"
        # If we reach the end of the sequence
        # start again
        if (StepCounter>=StepCount):
          StepCounter = 0
        if (StepCounter<0):
          StepCounter = StepCount+StepDir
        # Wait before moving on
        time.sleep(WaitTime)
      else:
        print >> sys.stderr,"Limit Reached"
        break
  except (KeyboardInterrupt, SystemExit):
    for pin in StepPins:
      f = open(LOG_FILE2,'a')
      f.write(str(currposition)+"\n")
      f.close()
      print >> sys.stdout,str(currposition)
      GPIO.output(pin, False)
    raise