uln200xa: Initial implementation

This driver was tested on a Grove Geared Stepper with Driver, the
uln2003a paired with a 28BYJ-48 unipolar stepper motor.

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: John Van Drasek <john.r.van.drasek@intel.com>

examples/python/uln200xa.py

@@ -0,0 +1,66 @@
+#!/usr/bin/python
+# Author:  Jon Trulson <jtrulson@ics.com>
+# Copyright (c) 2015 Intel Corporation.
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+
+import time, sys, signal, atexit
+import pyupm_uln200xa as upmULN200XA
+
+# Instantiate a Stepper motor on a ULN200XA Darlington Motor Driver
+# This was tested with the Grove Geared Step Motor with Driver
+
+# Instantiate a ULN2003XA stepper object
+myUln200xa = upmULN200XA.ULN200XA(4096, 8, 9, 10, 11)
+
+## Exit handlers ##
+# This stops python from printing a stacktrace when you hit control-C
+def SIGINTHandler(signum, frame):
+	raise SystemExit
+
+# This lets you run code on exit,
+# including functions from myUln200xa
+def exitHandler():
+	print "Exiting"
+	sys.exit(0)
+
+# Register exit handlers
+atexit.register(exitHandler)
+signal.signal(signal.SIGINT, SIGINTHandler)
+
+
+myUln200xa.setSpeed(5) # 5 RPMs
+myUln200xa.setDirection(upmULN200XA.ULN200XA.DIR_CW)
+
+print "Rotating 1 revolution clockwise."
+myUln200xa.stepperSteps(4096)
+
+print "Sleeping for 2 seconds..."
+time.sleep(2)
+
+print "Rotating 1/2 revolution counter clockwise."
+myUln200xa.setDirection(upmULN200XA.ULN200XA.DIR_CCW)
+myUln200xa.stepperSteps(2048)
+
+# release
+myUln200xa.release()
+
+# exitHandler is called automatically