ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_Lanbao.cpp

126 lines
3.9 KiB
C++

/*
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);
}
}