adafruitms1438: Initial implementation

The library implements support for the Adafruit MotorShield 1438:
http://www.adafruit.com/products/1438

This shield supports 4 DC motors or 2 Stepper motors.

It makes use of the pca9685 UPM library, and therefore requires that
PR #123 and PR #134 are merged first:

PR 123: pkgconfig.in: allow a module to specify dependencies on
another module

PR 134: pca9685: Initial implementation

Signed-off-by: Jon Trulson <jtrulson@ics.com>
Signed-off-by: Zion Orent <zorent@ics.com>
Signed-off-by: Mihai Tudor Panu <mihai.tudor.panu@intel.com>

examples/c++/adafruitms1438-stepper.cxx

@@ -0,0 +1,82 @@
+/*
+ * 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.
+ */
+
+#include <unistd.h>
+#include <signal.h>
+#include <iostream>
+#include "adafruitms1438.h"
+
+using namespace std;
+using namespace upm;
+
+int main(int argc, char **argv)
+{
+//! [Interesting]
+  // Instantiate an Adafruit MS 1438 on I2C bus 0
+
+  upm::AdafruitMS1438 *ms = 
+    new upm::AdafruitMS1438(ADAFRUITMS1438_I2C_BUS, 
+                            ADAFRUITMS1438_DEFAULT_I2C_ADDR);
+
+  // Setup for use with a stepper motor connected to the M1 & M2 ports
+
+  // set a PWM period of 50Hz
+
+  // disable first, to be safe
+  ms->disableStepper(AdafruitMS1438::STEPMOTOR_M12);
+
+  // configure for a NEMA-17, 200 steps per revolution
+  ms->stepConfig(AdafruitMS1438::STEPMOTOR_M12, 200);
+
+  // set speed at 10 RPM's
+  ms->setStepperSpeed(AdafruitMS1438::STEPMOTOR_M12, 10);
+  ms->setStepperDirection(AdafruitMS1438::STEPMOTOR_M12, 
+                          AdafruitMS1438::DIR_CW);
+
+  // enable
+  cout << "Enabling..." << endl;
+  ms->enableStepper(AdafruitMS1438::STEPMOTOR_M12);
+
+  cout << "Rotating 1 full revolution at 10 RPM speed." << endl;
+  ms->stepperSteps(AdafruitMS1438::STEPMOTOR_M12, 200);
+
+  cout << "Sleeping for 2 seconds..." << endl;
+  sleep(2);
+  cout << "Rotating 1/2 revolution in opposite direction at 10 RPM speed." 
+       << endl;
+
+  ms->setStepperDirection(AdafruitMS1438::STEPMOTOR_M12, 
+                          AdafruitMS1438::DIR_CCW);
+  ms->stepperSteps(AdafruitMS1438::STEPMOTOR_M12, 100);
+
+  cout << "Disabling..." << endl;
+  ms->disableStepper(AdafruitMS1438::STEPMOTOR_M12);
+
+  cout << "Exiting" << endl;
+
+//! [Interesting]
+
+  delete ms;
+  return 0;
+}