urm37: Add C library for this sensor

Added a C implementation for this sensor.  The C++ library was changed
to just wrap the C library calls.

Signed-off-by: Jon Trulson <jtrulson@ics.com>

examples/c/CMakeLists.txt

@@ -90,3 +90,5 @@ add_example (dfrph)
 add_example (vk2828u7)
 add_example (mma7361)
 add_example (bh1750)
+add_example (urm37)
+add_example (urm37-uart)

examples/c/urm37-uart.c

@@ -0,0 +1,75 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 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 "urm37.h"
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+  if (signo == SIGINT)
+    shouldRun = false;
+}
+
+int main()
+{
+  signal(SIGINT, sig_handler);
+
+//! [Interesting]
+
+  // Instantiate a URM37 sensor on UART 0, with the reset pin on D2
+  urm37_context sensor = urm37_init(0, 2, 0, 0, 0, false);
+
+  if (!sensor)
+    {
+      printf("urm37_init() failed.\n");
+      return(1);
+    }
+
+  // Every half a second, sample the URM37 and output the measured
+  // distance in cm.
+
+  while (shouldRun)
+    {
+      float distance, temperature;
+
+      urm37_get_distance(sensor, &distance, 0);
+      printf("Detected distance (cm): %f\n", distance);
+
+      urm37_get_temperature(sensor, &temperature);
+      printf("Temperature (C): %f\n\n", temperature);
+      usleep(500000);
+    }
+
+//! [Interesting]
+
+  printf("Exiting\n");
+
+  urm37_close(sensor);
+
+  return 0;
+}

examples/c/urm37.c

@@ -0,0 +1,73 @@
+/*
+ * Author: Jon Trulson <jtrulson@ics.com>
+ * Copyright (c) 2016 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 "urm37.h"
+
+bool shouldRun = true;
+
+void sig_handler(int signo)
+{
+  if (signo == SIGINT)
+    shouldRun = false;
+}
+
+int main()
+{
+  signal(SIGINT, sig_handler);
+
+//! [Interesting]
+
+  // Instantiate a URM37 sensor on analog pin A0, reset pin on D2,
+  // trigger pin on D3 with an analog reference voltage of 5.0
+  urm37_context sensor = urm37_init(0, 2, 3, 5.0, 0, true);
+
+  if (!sensor)
+    {
+      printf("urm37_init() failed.\n");
+      return(1);
+    }
+
+  // Every half a second, sample the URM37 and output the measured
+  // distance in cm.
+
+  while (shouldRun)
+    {
+      float distance;
+
+      urm37_get_distance(sensor, &distance, 0);
+      printf("Detected distance (cm): %f\n", distance);
+      usleep(500000);
+    }
+
+//! [Interesting]
+
+  printf("Exiting\n");
+
+  urm37_close(sensor);
+
+  return 0;
+}