AP_RangeFinder: added driver for Lanbao CM8JL65

libraries/AP_RangeFinder/AP_RangeFinder_Lanbao.cpp

@@ -0,0 +1,125 @@
+/*
+   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/>.
+ */
+/*
+  driver for Lanbao PSK-CM8JL65-CC5 Lidar
+ */
+#include <AP_HAL/AP_HAL.h>
+#include "AP_RangeFinder_Lanbao.h"
+#include <AP_SerialManager/AP_SerialManager.h>
+#include <AP_Math/crc.h>
+#include <stdio.h>
+
+extern const AP_HAL::HAL& hal;
+
+/*
+  this sensor has no way of reporting "out of range", it will keep
+  reporting distances at of around 7 to 8 meters even when pointed at
+  the sky. For this reason we limit the max range to 6 meters as
+  otherwise we may be giving false data
+ */
+#define LANBAO_MAX_RANGE_CM 600
+
+/*
+   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_Lanbao::AP_RangeFinder_Lanbao(RangeFinder::RangeFinder_State &_state,
+                                             AP_RangeFinder_Params &_params,
+                                             uint8_t serial_instance) :
+    AP_RangeFinder_Backend(_state, _params)
+{
+    const AP_SerialManager &serial_manager = AP::serialmanager();
+    uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
+    if (uart != nullptr) {
+        // always 115200
+        uart->begin(115200);
+    }
+}
+
+/* 
+   detect if a 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_Lanbao::detect(uint8_t serial_instance)
+{
+    return AP::serialmanager().find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != nullptr;
+}
+
+
+// read - return last value measured by sensor
+bool AP_RangeFinder_Lanbao::get_reading(uint16_t &reading_cm)
+{
+    if (uart == nullptr) {
+        return false;
+    }
+
+    float sum_range = 0;
+    uint32_t count = 0;
+
+    // format is: [ 0xA5 | 0x5A | distance-MSB-mm | distance-LSB-mm | crc16 ]
+
+    // read any available lines from the lidar
+    int16_t nbytes = uart->available();
+    while (nbytes-- > 0) {
+        int16_t b = uart->read();
+        if (b == -1) {
+            break;
+        }
+        if (buf_len == 0 && b != 0xA5) {
+            // discard
+            continue;
+        }
+        if (buf_len == 1 && b != 0x5A) {
+            // discard
+            if (b == 0xA5) {
+                buf[0] = b;
+            } else {
+                buf_len = 0;
+            }
+            continue;
+        }
+        buf[buf_len++] = b;
+        if (buf_len == sizeof(buf)) {
+            buf_len = 0;
+            uint16_t crc = (buf[5]<<8) | buf[4];
+            if (crc != calc_crc_modbus(buf, 4)) {
+                // bad CRC, discard
+                continue;
+            }
+            sum_range += float((buf[2]<<8) | buf[3]) * 0.001;
+            count++;
+        }
+    }
+    if (count > 0) {
+        reading_cm = (sum_range / count) * 100;
+        return reading_cm <= LANBAO_MAX_RANGE_CM?true:false;
+    }
+    return false;
+}
+
+/* 
+   update the state of the sensor
+*/
+void AP_RangeFinder_Lanbao::update(void)
+{
+    if (get_reading(state.distance_cm)) {
+        // update range_valid state based on distance measured
+        state.last_reading_ms = AP_HAL::millis();
+        update_status();
+    } else if (AP_HAL::millis() - state.last_reading_ms > 200) {
+        set_status(RangeFinder::RangeFinder_NoData);
+    }
+}

libraries/AP_RangeFinder/AP_RangeFinder_Lanbao.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "RangeFinder.h"
+#include "RangeFinder_Backend.h"
+
+class AP_RangeFinder_Lanbao : public AP_RangeFinder_Backend
+{
+
+public:
+    // constructor
+    AP_RangeFinder_Lanbao(RangeFinder::RangeFinder_State &_state,
+                          AP_RangeFinder_Params &_params,
+                          uint8_t serial_instance);
+
+    // static detection function
+    static bool detect(uint8_t serial_instance);
+
+    // update state
+    void update(void) override;
+
+protected:
+
+    virtual MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override {
+        return MAV_DISTANCE_SENSOR_LASER;
+    }
+
+private:
+    // get a reading
+    bool get_reading(uint16_t &reading_cm);
+
+    AP_HAL::UARTDriver *uart = nullptr;
+    uint8_t buf[6];
+    uint8_t buf_len = 0;
+};

libraries/AP_RangeFinder/RangeFinder.cpp

@@ -39,6 +39,7 @@
 #include "AP_RangeFinder_PWM.h"
 #include "AP_RangeFinder_BLPing.h"
 #include "AP_RangeFinder_UAVCAN.h"
+#include "AP_RangeFinder_Lanbao.h"
 
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include <AP_Logger/AP_Logger.h>
@@ -512,6 +513,11 @@ void RangeFinder::detect_instance(uint8_t instance, uint8_t& serial_instance)
             drivers[instance] = new AP_RangeFinder_BLPing(state[instance], params[instance], serial_instance++);
         }
         break;
+    case RangeFinder_TYPE_Lanbao:
+        if (AP_RangeFinder_Lanbao::detect(serial_instance)) {
+            drivers[instance] = new AP_RangeFinder_Lanbao(state[instance], params[instance], serial_instance++);
+        }
+        break;
     default:
         break;
     }

libraries/AP_RangeFinder/RangeFinder.h

@@ -72,6 +72,7 @@ public:
         RangeFinder_TYPE_BLPing = 23,
         RangeFinder_TYPE_UAVCAN = 24,
         RangeFinder_TYPE_BenewakeTFminiPlus = 25,
+        RangeFinder_TYPE_Lanbao = 26,
     };
 
     enum RangeFinder_Function {