AP_RangeFinder: add LeddarOne support

libraries/AP_RangeFinder/AP_RangeFinder_LeddarOne.cpp

@@ -0,0 +1,224 @@
+// -*- 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_LeddarOne.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_LeddarOne::AP_RangeFinder_LeddarOne(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 LeddarOne 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_LeddarOne::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_LeddarOne::get_reading(uint16_t &reading_cm)
+{
+    if (uart == nullptr) {
+        return false;
+    }
+
+    // send a request message for Modbus function 4
+    if (send_request() < 0) {
+        return false;
+    }
+
+    uint32_t start_ms = AP_HAL::millis();
+    while (!uart->available()) {
+        // wait up to 200ms
+        if (AP_HAL::millis() - start_ms > 200) {
+            return false;
+        }
+    }
+
+    // parse a response message, set detections and sum_distance
+    if (parse_response() <= 0) {
+        return false;
+    }
+
+    // calculate average distance
+    reading_cm = sum_distance / number_detections;
+
+    return true;
+}
+
+/*
+   update the state of the sensor
+*/
+void AP_RangeFinder_LeddarOne::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);
+    }
+}
+
+/*
+   CRC16
+   CRC-16-IBM(x16+x15+x2+1)
+*/
+bool AP_RangeFinder_LeddarOne::CRC16(uint8_t *aBuffer, uint8_t aLength, bool aCheck)
+{
+    uint16_t crc = 0xFFFF;
+    uint32_t i = 0;
+    uint32_t j = 0;
+    uint8_t lCRCHi = 0;
+    uint8_t lCRCLo = 0;
+
+    for (i=0; i<aLength; i++) {
+        crc ^= aBuffer[i];
+        for (j=0; j<8; j++) {
+            if (crc & 1) {
+                crc = (crc >> 1) ^ 0xA001;
+            } else {
+                crc >>= 1;
+            }
+        }
+    }
+
+    lCRCLo = LOWBYTE(crc);
+    lCRCHi = HIGHBYTE(crc);
+
+    if (aCheck) {
+        return (aBuffer[aLength] == lCRCLo) && (aBuffer[aLength+1] == lCRCHi);
+    } else {
+        aBuffer[aLength] = lCRCLo;
+        aBuffer[aLength+1] = lCRCHi;
+        return true;
+    }
+}
+
+/*
+   send a request message to execute ModBus function 0x04
+ */
+int8_t AP_RangeFinder_LeddarOne::send_request(void)
+{
+    uint8_t data_buffer[10] = {0};
+    uint8_t i = 0;
+
+    int32_t nbytes = uart->available();
+
+    // clear buffer
+    while (nbytes-- > 0) {
+        uart->read();
+        if (++i > 250) {
+            return LEDDARONE_ERR_SERIAL_PORT;
+        }
+    }
+
+    // Modbus read input register (function code 0x04)
+    data_buffer[0] = LEDDARONE_DEFAULT_ADDRESS;
+    data_buffer[1] = 0x04;
+    data_buffer[2] = 0;
+    data_buffer[3] = 20;
+    data_buffer[4] = 0;
+    data_buffer[5] = 10;
+
+    // CRC16
+    CRC16(data_buffer, 6, false);
+
+    // write buffer data with CRC16 bits
+    for (i=0; i<8; i++) {
+        uart->write(data_buffer[i]);
+    }
+    uart->flush();
+
+    return 0;
+}
+
+ /*
+    parse a response message from Modbus
+  */
+int8_t AP_RangeFinder_LeddarOne::parse_response(void)
+{
+    uint8_t data_buffer[25] = {0};
+    uint32_t start_ms = AP_HAL::millis();
+    uint32_t nbytes = 0;
+    uint32_t len =0;
+    uint8_t i = 0;
+    uint8_t index_offset = 11;
+
+    // read serial
+    while (AP_HAL::millis() - start_ms < 10) {
+        nbytes = uart->available();
+        if (len == 25 && nbytes == 0) {
+            break;
+        } else {
+            for (i=len; i<nbytes+len; i++) {
+                if (i >= 25) {
+                    return LEDDARONE_ERR_BAD_RESPONSE;
+                }
+                data_buffer[i] = uart->read();
+            }
+            start_ms = AP_HAL::millis();
+            len += nbytes;
+        }
+    }
+
+    if (len != 25) {
+    	return LEDDARONE_ERR_BAD_RESPONSE;
+    }
+
+    // CRC16
+    if (!CRC16(data_buffer, len-2, true)) {
+        return LEDDARONE_ERR_BAD_CRC;
+    }
+
+    // number of detections
+    number_detections = data_buffer[10];
+
+    // if the number of detection is over , it is false
+    if (number_detections > (sizeof(detections) / sizeof(detections[0]))) {
+        return LEDDARONE_ERR_NUMBER_DETECTIONS;
+    }
+
+    memset(detections, 0, sizeof(detections));
+    sum_distance = 0;
+    for (i=0; i<number_detections; i++) {
+        // mm to cm
+        detections[i] =  (((uint16_t)data_buffer[index_offset])*256 + data_buffer[index_offset+1]) / 10;
+        sum_distance += detections[i];
+        index_offset += 4;
+    }
+
+    return number_detections;
+}

libraries/AP_RangeFinder/AP_RangeFinder_LeddarOne.h

@@ -0,0 +1,52 @@
+// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
+#pragma once
+
+#include "RangeFinder.h"
+#include "RangeFinder_Backend.h"
+#include <GCS_MAVLink/GCS.h>
+
+// default slave address
+#define LEDDARONE_DEFAULT_ADDRESS 0x01
+
+// error codes
+#define LEDDARONE_ERR_BAD_CRC -1
+#define LEDDARONE_ERR_NO_RESPONSES -2
+#define LEDDARONE_ERR_BAD_RESPONSE -3
+#define LEDDARONE_ERR_SHORT_RESPONSE -4
+#define LEDDARONE_ERR_SERIAL_PORT -5
+#define LEDDARONE_ERR_NUMBER_DETECTIONS -6
+
+class AP_RangeFinder_LeddarOne : public AP_RangeFinder_Backend
+{
+
+public:
+    // constructor
+    AP_RangeFinder_LeddarOne(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);
+
+    // CRC16
+    bool CRC16(uint8_t *aBuffer, uint8_t aLength, bool aCheck);
+
+    // send a request message to execute ModBus function
+    int8_t send_request(void);
+
+    // parse a response message from ModBus
+    int8_t parse_response(void);
+
+    AP_HAL::UARTDriver *uart = nullptr;
+    uint32_t last_reading_ms = 0;
+
+    uint16_t detections[3];
+    uint8_t number_detections = 0;
+    uint32_t sum_distance = 0;
+};

libraries/AP_RangeFinder/RangeFinder.cpp

@@ -25,6 +25,7 @@
 #include "AP_RangeFinder_LightWareSerial.h"
 #include "AP_RangeFinder_Bebop.h"
 #include "AP_RangeFinder_MAVLink.h"
+#include "AP_RangeFinder_LeddarOne.h"
 
 extern const AP_HAL::HAL &hal;
 
@@ -537,6 +538,13 @@ void RangeFinder::detect_instance(uint8_t instance)
             return;
         }
     }
+    if (type == RangeFinder_TYPE_LEDDARONE) {
+        if (AP_RangeFinder_LeddarOne::detect(*this, instance, serial_manager)) {
+            state[instance].instance = instance;
+            drivers[instance] = new AP_RangeFinder_LeddarOne(*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

@@ -48,7 +48,8 @@ public:
         RangeFinder_TYPE_LWI2C  = 7,
         RangeFinder_TYPE_LWSER  = 8,
         RangeFinder_TYPE_BEBOP  = 9,
-        RangeFinder_TYPE_MAVLink = 10
+        RangeFinder_TYPE_MAVLink = 10,
+        RangeFinder_TYPE_LEDDARONE = 12
     };
 
     enum RangeFinder_Function {