AP_RangeFinder: Add support for Aerotenna uLanding radar altimeter

libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp

@@ -0,0 +1,104 @@
+// -*- 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_uLanding.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_uLanding::AP_RangeFinder_uLanding(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_Aerotenna_uLanding, 0);
+    if (uart != nullptr) {
+        uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Aerotenna_uLanding, 0));
+    }
+}
+
+/*
+   detect if a uLanding 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_uLanding::detect(RangeFinder &_ranger, uint8_t instance, AP_SerialManager &serial_manager)
+{
+    return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Aerotenna_uLanding, 0) != nullptr;
+}
+
+// read - return last value measured by sensor
+bool AP_RangeFinder_uLanding::get_reading(uint16_t &reading_cm)
+{
+    if (uart == nullptr) {
+        return false;
+    }
+
+    // read any available lines from the uLanding
+    float sum = 0;
+    uint16_t count = 0;
+    uint8_t  index = 0;
+
+    int16_t nbytes = uart->available();
+    while (nbytes-- > 0) {
+        uint8_t c = uart->read();
+        // ok, we have located start byte
+        if ( c == 72 && index ==0 ) {
+            linebuf_len = 0;
+            index       = 1;
+        }
+        // now it is ready to decode index information
+        if ( index == 1 ){
+        	linebuf[linebuf_len] = c;
+        	linebuf_len ++;
+        	if ( linebuf_len == 3 ){
+        		index = 0;
+        		sum += ( linebuf[2]&0x7F ) *128 + ( linebuf[1]&0x7F );
+        		linebuf_len = 0;
+        		count ++;
+        	}
+        }
+
+    }
+
+    if (count == 0) {
+        return false;
+    }
+    //reading_cm = 4.5 * sum / count;
+    reading_cm = 2.5 * sum / count;
+    return true;
+}
+
+/*
+   update the state of the sensor
+*/
+void AP_RangeFinder_uLanding::update(void)
+{
+    if (get_reading(state.distance_cm)) {
+        // update range_valid state based on distance measured
+        last_reading_ms = AP_HAL::millis();
+        update_status();
+    } else if (AP_HAL::millis() - last_reading_ms > 200) {
+        set_status(RangeFinder::RangeFinder_NoData);
+    }
+}

libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h

@@ -0,0 +1,31 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#pragma once
+
+#include "RangeFinder.h"
+#include "RangeFinder_Backend.h"
+
+class AP_RangeFinder_uLanding : public AP_RangeFinder_Backend
+{
+
+public:
+    // constructor
+	AP_RangeFinder_uLanding(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;
+    uint8_t linebuf[10];
+    uint8_t linebuf_len = 0;
+};
+
+

libraries/AP_RangeFinder/RangeFinder.cpp

@@ -25,6 +25,7 @@
 #include "AP_RangeFinder_Bebop.h"
 #include "AP_RangeFinder_MAVLink.h"
 #include "AP_RangeFinder_LeddarOne.h"
+#include "AP_RangeFinder_uLanding.h"
 #include <AP_BoardConfig/AP_BoardConfig.h>
 
 extern const AP_HAL::HAL &hal;
@@ -637,6 +638,13 @@ void RangeFinder::detect_instance(uint8_t instance)
             return;
         }
     }
+    if (type == RangeFinder_TYPE_ULANDING) {
+        if (AP_RangeFinder_uLanding::detect(*this, instance, serial_manager)) {
+            state[instance].instance = instance;
+            drivers[instance] = new AP_RangeFinder_uLanding(*this, instance, state[instance], serial_manager);
+            return;
+        }
+    }
 #if (CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BEBOP || \
      CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_DISCO) && defined(HAVE_LIBIIO)
     if (type == RangeFinder_TYPE_BEBOP) {

libraries/AP_RangeFinder/RangeFinder.h

@@ -48,6 +48,7 @@ public:
         RangeFinder_TYPE_LWSER  = 8,
         RangeFinder_TYPE_BEBOP  = 9,
         RangeFinder_TYPE_MAVLink = 10,
+        RangeFinder_TYPE_ULANDING= 11,
         RangeFinder_TYPE_LEDDARONE = 12
     };