AP_RangeFinder: added lightware serial rangefinder

libraries/AP_RangeFinder/AP_RangeFinder_LightWareSerial.cpp

@@ -0,0 +1,99 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+/*
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <AP_HAL/AP_HAL.h>
+#include "AP_RangeFinder_LightWareSerial.h"
+#include <AP_SerialManager/AP_SerialManager.h>
+#include <ctype.h>
+
+extern const AP_HAL::HAL& hal;
+
+/* 
+   The constructor also initialises the rangefinder. Note that this
+   constructor is not called until detect() returns true, so we
+   already know that we should setup the rangefinder
+*/
+AP_RangeFinder_LightWareSerial::AP_RangeFinder_LightWareSerial(RangeFinder &_ranger, uint8_t instance,
+                                                               RangeFinder::RangeFinder_State &_state,
+                                                               AP_SerialManager &serial_manager) :
+    AP_RangeFinder_Backend(_ranger, instance, _state)
+{
+    uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Lidar, 0);
+    if (uart != nullptr) {
+        uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Lidar, 0));
+    }
+}
+
+/* 
+   detect if a Lightware rangefinder is connected. We'll detect by
+   trying to take a reading on Serial. If we get a result the sensor is
+   there.
+*/
+bool AP_RangeFinder_LightWareSerial::detect(RangeFinder &_ranger, uint8_t instance, AP_SerialManager &serial_manager)
+{
+    return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Lidar, 0) != nullptr;
+}
+
+// read - return last value measured by sensor
+bool AP_RangeFinder_LightWareSerial::get_reading(uint16_t &reading_cm)
+{
+    if (uart == nullptr) {
+        return false;
+    }
+
+    // read any available lines from the lidar
+    float sum = 0;
+    uint16_t count = 0;
+    int16_t nbytes = uart->available();
+    while (nbytes-- > 0) {
+        char c = uart->read();
+        if (c == '\r') {
+            linebuf[linebuf_len] = 0;
+            sum += atof(linebuf);
+            count++;
+            linebuf_len = 0;
+        } else if (isdigit(c) || c == '.') {
+            linebuf[linebuf_len++] = c;
+            if (linebuf_len == sizeof(linebuf)) {
+                // too long, discard the line
+                linebuf_len = 0;
+            }
+        }
+    }
+
+    // we need to write a byte to prompt another reading
+    uart->write('\n');
+
+    if (count == 0) {
+        return false;
+    }
+    reading_cm = 100 * sum / count;
+    return true;
+}
+
+/* 
+   update the state of the sensor
+*/
+void AP_RangeFinder_LightWareSerial::update(void)
+{
+    if (get_reading(state.distance_cm)) {
+        // update range_valid state based on distance measured
+        last_reading_ms = hal.scheduler->millis();
+        update_status();
+    } else if (hal.scheduler->millis() - last_reading_ms > 200) {
+        set_status(RangeFinder::RangeFinder_NoData);
+    }
+}

libraries/AP_RangeFinder/AP_RangeFinder_LightWareSerial.h

@@ -0,0 +1,32 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+
+#ifndef __AP_RANGEFINDER_LIGHTWARESERIAL_H__
+#define __AP_RANGEFINDER_LIGHTWARESERIAL_H__
+
+#include "RangeFinder.h"
+#include "RangeFinder_Backend.h"
+
+class AP_RangeFinder_LightWareSerial : public AP_RangeFinder_Backend
+{
+
+public:
+    // constructor
+    AP_RangeFinder_LightWareSerial(RangeFinder &ranger, uint8_t instance, RangeFinder::RangeFinder_State &_state,
+                                   AP_SerialManager &serial_manager);
+
+    // static detection function
+    static bool detect(RangeFinder &ranger, uint8_t instance, AP_SerialManager &serial_manager);
+
+    // update state
+    void update(void);
+
+private:
+    // get a reading
+    bool get_reading(uint16_t &reading_cm);
+
+    AP_HAL::UARTDriver *uart = nullptr;
+    uint32_t last_reading_ms = 0;
+    char linebuf[10];
+    uint8_t linebuf_len = 0;
+};
+#endif  // __AP_RANGEFINDER_LIGHTWARESERIAL_H__

libraries/AP_RangeFinder/RangeFinder.cpp

@@ -22,6 +22,7 @@
 #include "AP_RangeFinder_PX4_PWM.h"
 #include "AP_RangeFinder_BBB_PRU.h"
 #include "AP_RangeFinder_LightWareI2C.h"
+#include "AP_RangeFinder_LightWareSerial.h"
 
 // table of user settable parameters
 const AP_Param::GroupInfo RangeFinder::var_info[] PROGMEM = {
@@ -205,10 +206,11 @@ const AP_Param::GroupInfo RangeFinder::var_info[] PROGMEM = {
     AP_GROUPEND
 };
 
-RangeFinder::RangeFinder(void) :
+RangeFinder::RangeFinder(AP_SerialManager &_serial_manager) :
     primary_instance(0),
     num_instances(0),
-    estimated_terrain_height(0)
+    estimated_terrain_height(0),
+    serial_manager(_serial_manager)
 {
     AP_Param::setup_object_defaults(this, var_info);
 
@@ -332,6 +334,13 @@ void RangeFinder::detect_instance(uint8_t instance)
         }
     }
 #endif
+    if (type == RangeFinder_TYPE_LWSER) {
+        if (AP_RangeFinder_LightWareSerial::detect(*this, instance, serial_manager)) {
+            state[instance].instance = instance;
+            drivers[instance] = new AP_RangeFinder_LightWareSerial(*this, instance, state[instance], serial_manager);
+            return;
+        }
+    } 
     if (type == RangeFinder_TYPE_ANALOG) {
         // note that analog must be the last to be checked, as it will
         // always come back as present if the pin is valid

libraries/AP_RangeFinder/RangeFinder.h

@@ -21,6 +21,7 @@
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Param/AP_Param.h>
 #include <AP_Math/AP_Math.h>
+#include <AP_SerialManager/AP_SerialManager.h>
 
 // Maximum number of range finder instances available on this platform
 #define RANGEFINDER_MAX_INSTANCES 2
@@ -35,7 +36,7 @@ class RangeFinder
 public:
     friend class AP_RangeFinder_Backend;
 
-    RangeFinder(void);
+    RangeFinder(AP_SerialManager &_serial_manager);
 
     // RangeFinder driver types
     enum RangeFinder_Type {
@@ -46,7 +47,8 @@ public:
         RangeFinder_TYPE_PX4    = 4,
         RangeFinder_TYPE_PX4_PWM= 5,
         RangeFinder_TYPE_BBB_PRU= 6,
-        RangeFinder_TYPE_LWI2C  = 7
+        RangeFinder_TYPE_LWI2C  = 7,
+        RangeFinder_TYPE_LWSER  = 8
     };
 
     enum RangeFinder_Function {
@@ -182,6 +184,7 @@ private:
     uint8_t primary_instance:2;
     uint8_t num_instances:2;
     float estimated_terrain_height;
+    AP_SerialManager &serial_manager;
 
     void detect_instance(uint8_t instance);
     void update_instance(uint8_t instance);  

libraries/AP_RangeFinder/examples/RFIND_test/RFIND_test.cpp

@@ -34,10 +34,12 @@
 #include <AP_Scheduler/AP_Scheduler.h>
 #include <AP_BattMonitor/AP_BattMonitor.h>
 #include <AP_Rally/AP_Rally.h>
+#include <AP_SerialManager/AP_SerialManager.h>
 
 const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;
 
-static RangeFinder sonar;
+static AP_SerialManager serial_manager;
+static RangeFinder sonar {serial_manager};
 
 void setup()
 {