New example using MODE pin for STATUS output

This example shows a method for running the LIDAR-Lite v3 HP while
monitoring busy status via the MODE pin on the device. Using the
MODE pin and the selected configuration, this example illustrates
a higher speed implementation that can be used for shorter distances.

Change-Id: I56c64be05dda3416540c58e045450888d75942fa

examples/v3HP/v3HP_MONITOR/v3HP_MONITOR.ino

@@ -0,0 +1,126 @@
+/*------------------------------------------------------------------------------
+
+  LIDARLite Arduino Library
+  v3HP/v3HP_I2C
+
+  This example shows a method for running the LIDAR-Lite v3 HP while monitoring
+  busy status via the MODE pin on the device. Using the MODE pin and the
+  selected configuration, this example illustrates a higher speed implementation
+  that can be used for shorter distances.
+
+  Open a serial terminal program
+  (or the Serial Monitor in the Arduino IDE) to view distance measurements.
+
+  Connections:
+  LIDAR-Lite 5 Vdc (red) to Arduino 5v
+  LIDAR-Lite I2C SCL (green) to Arduino SCL
+  LIDAR-Lite I2C SDA (blue) to Arduino SDA
+  LIDAR-Lite Ground (black) to Arduino GND
+  LIDAR-Lite MODE (yellow) to Arduino pin 3
+
+  (Capacitor recommended to mitigate inrush current when device is enabled)
+  680uF capacitor (+) to Arduino 5v
+  680uF capacitor (-) to Arduino GND
+
+  See the Operation Manual for wiring diagrams and more information:
+  http://static.garmin.com/pumac/LIDAR_Lite_v3HP_Operation_Manual_and_Technical_Specifications.pdf
+
+------------------------------------------------------------------------------*/
+
+#include <stdint.h>
+#include <Wire.h>
+#include "LIDARLite_v3HP.h"
+
+LIDARLite_v3HP myLidarLite;
+
+#define FAST_I2C
+//#define EXTERNAL_PULLUP
+
+#define MonitorPin    3
+#define TriggerPin    2
+
+void setup()
+{
+    // Initialize Arduino serial port (for display of ASCII output to PC)
+    Serial.begin(115200);
+
+    // Initialize Arduino I2C (for communication to LidarLite)
+    Wire.begin();
+    #ifdef FAST_I2C
+        #if ARDUINO >= 157
+            Wire.setClock(400000UL); // Set I2C frequency to 400kHz (for Arduino Due)
+        #else
+            TWBR = ((F_CPU / 400000UL) - 16) / 2; // Set I2C frequency to 400kHz
+        #endif
+    #endif
+
+    // Configuration '6' sets the mode select bits in the acquisition config
+    // register to 01 and configures other settings to enable high rep rates.
+    myLidarLite.configure(6);
+
+    #ifdef EXTERNAL_PULLUP
+        // Standard configuration of the monitor and trigger pins as
+        // shown in the operation manual
+        pinMode(MonitorPin, INPUT);
+        pinMode(TriggerPin, OUTPUT);
+        digitalWrite(TriggerPin, HIGH);
+    #else
+        // When no external pullup to the trigger pin is installed the
+        // monitor pin can be used by itself using an internal pullup in the micro
+        pinMode(MonitorPin, INPUT_PULLUP);
+    #endif
+}
+
+void loop()
+{
+    uint16_t distance    = 0;
+    uint8_t  newDistance = 0;
+
+    // Continuous loop
+    while (1)
+    {
+        newDistance = distanceContinuous(&distance);
+
+        // When there is new distance data, print it to the serial port
+        if (newDistance)
+        {
+            Serial.println(distance);
+        }
+    }
+}
+
+//---------------------------------------------------------------------
+// Read Continuous Distance Measurements
+//
+// To use the function, the MODE pin must first be configured for
+// status output mode via the acquisition configuration register.
+//
+// The most recent distance measurement can always be read from
+// device registers. Monitoring the BUSY flag via the MODE pin
+// can alert the user that the distance measurement is new
+// and that the next measurement can be initiated. If the device is
+// BUSY this function does nothing and returns 0. If the device is
+// NOT BUSY this function triggers the next measurement, reads the
+// distance data from the previous measurement, and returns 1.
+//---------------------------------------------------------------------
+uint8_t distanceContinuous(uint16_t * distance)
+{
+    uint8_t newDistance = 0;
+
+    // Check on busyFlag to indicate if device is idle
+    // (meaning = it finished the previously triggered measurement)
+    if (digitalRead(MonitorPin))
+    {
+        // Trigger the next range measurement
+        myLidarLite.takeRange();
+
+        // Read new distance data from device registers
+        *distance = myLidarLite.readDistance();
+
+        // Report to calling function that we have new data
+        newDistance = 1;
+    }
+
+    return newDistance;
+}
+