ardupilot/libraries/AP_Proximity/AP_Proximity_TeraRangerTowe...

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/*
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_Proximity_TeraRangerTower.h"
#include <AP_Math/crc.h>
#include <ctype.h>
#include <stdio.h>
extern const AP_HAL::HAL& hal;
// update the state of the sensor
void AP_Proximity_TeraRangerTower::update(void)
{
if (_uart == nullptr) {
return;
}
// process incoming messages
read_sensor_data();
// check for timeout and set health status
if ((_last_distance_received_ms == 0) || (AP_HAL::millis() - _last_distance_received_ms > PROXIMITY_TRTOWER_TIMEOUT_MS)) {
set_status(AP_Proximity::Status::NoData);
} else {
set_status(AP_Proximity::Status::Good);
}
}
// get maximum and minimum distances (in meters) of primary sensor
float AP_Proximity_TeraRangerTower::distance_max() const
{
return 4.5f;
}
float AP_Proximity_TeraRangerTower::distance_min() const
{
return 0.20f;
}
// check for replies from sensor, returns true if at least one message was processed
bool AP_Proximity_TeraRangerTower::read_sensor_data()
{
if (_uart == nullptr) {
return false;
}
uint16_t message_count = 0;
int16_t nbytes = _uart->available();
while (nbytes-- > 0) {
char c = _uart->read();
if (c == 'T' ) {
buffer_count = 0;
}
buffer[buffer_count++] = c;
// we should always read 19 bytes THxxxxxxxxxxxxxxxxC
if (buffer_count >= 19){
buffer_count = 0;
// check if message has right CRC
if (crc_crc8(buffer, 18) == buffer[18]){
update_sector_data(0, UINT16_VALUE(buffer[2], buffer[3])); // d1
update_sector_data(45, UINT16_VALUE(buffer[16], buffer[17])); // d8
update_sector_data(90, UINT16_VALUE(buffer[14], buffer[15])); // d7
update_sector_data(135, UINT16_VALUE(buffer[12], buffer[13])); // d6
update_sector_data(180, UINT16_VALUE(buffer[10], buffer[11])); // d5
update_sector_data(225, UINT16_VALUE(buffer[8], buffer[9])); // d4
update_sector_data(270, UINT16_VALUE(buffer[6], buffer[7])); // d3
update_sector_data(315, UINT16_VALUE(buffer[4], buffer[5])); // d2
message_count++;
}
}
}
return (message_count > 0);
}
// process reply
void AP_Proximity_TeraRangerTower::update_sector_data(int16_t angle_deg, uint16_t distance_cm)
{
const uint8_t sector = convert_angle_to_sector(angle_deg);
_angle[sector] = angle_deg;
_distance[sector] = ((float) distance_cm) / 1000;
_distance_valid[sector] = distance_cm != 0xffff;
_last_distance_received_ms = AP_HAL::millis();
// update boundary used for avoidance
update_boundary_for_sector(sector, true);
}