ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_LightWareSer...

110 lines
3.7 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/>.
*/
#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::RangeFinder_State &_state,
AP_RangeFinder_Params &_params,
AP_SerialManager &serial_manager,
uint8_t serial_instance) :
AP_RangeFinder_Backend(_state, _params)
{
uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
if (uart != nullptr) {
uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance));
}
}
/*
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(AP_SerialManager &serial_manager, uint8_t serial_instance)
{
return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != 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 += (float)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;
}
}
}
uint32_t now = AP_HAL::millis();
if (last_init_ms == 0 ||
(now - last_init_ms > 1000 &&
now - state.last_reading_ms > 1000)) {
// send enough serial transitions to trigger LW20 into serial
// mode. It starts in dual I2C/serial mode, and wants to see
// enough transitions to switch into serial mode.
uart->write("www\r\n");
last_init_ms = now;
} else {
uart->write('d');
}
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
state.last_reading_ms = AP_HAL::millis();
update_status();
} else if (AP_HAL::millis() - state.last_reading_ms > 200) {
set_status(RangeFinder::RangeFinder_NoData);
}
}