ardupilot/libraries/AP_RangeFinder/AP_RangeFinder_GYUS42v2.cpp

73 lines
1.9 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/>.
*/
#include <AP_HAL/AP_HAL.h>
#include "AP_RangeFinder_GYUS42v2.h"
#include <ctype.h>
extern const AP_HAL::HAL& hal;
bool AP_RangeFinder_GYUS42v2::find_signature_in_buffer(uint8_t start)
{
for (uint8_t i=start; i<buffer_used; i++) {
if (buffer[i] == 0x5A) {
memmove(&buffer[0], &buffer[i], buffer_used-i);
buffer_used -= i;
return true;
}
}
// header byte not in buffer
buffer_used = 0;
return false;
}
// get_reading - read a value from the sensor
bool AP_RangeFinder_GYUS42v2::get_reading(float &reading_m)
{
if (uart == nullptr) {
return false;
}
const uint8_t num_read = uart->read(&buffer[buffer_used], ARRAY_SIZE(buffer)-buffer_used);
buffer_used += num_read;
if (buffer_used == 0) {
return false;
}
if (buffer[0] != 0x5A &&
!find_signature_in_buffer(1)) {
return false;
}
if (buffer_used < ARRAY_SIZE(buffer)) {
return false;
}
uint8_t sum = 0;
for (uint8_t i=0; i<6; i++) {
sum += buffer[i];
}
if (buffer[6] != sum) {
find_signature_in_buffer(1);
return false;
}
reading_m = (buffer[4] << 8 | buffer[5]) * 0.01f;
buffer_used = 0;
return true;
}