mirror of
https://github.com/ArduPilot/ardupilot
synced 2025-01-05 07:28:29 -04:00
108 lines
3.8 KiB
C++
108 lines
3.8 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "AP_RangeFinder_config.h"
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#if AP_RANGEFINDER_JRE_SERIAL_ENABLED
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#include "AP_RangeFinder_JRE_Serial.h"
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#include <AP_Math/AP_Math.h>
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#define FRAME_HEADER_1 'R' // 0x52
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#define FRAME_HEADER_2_A 'A' // 0x41
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#define FRAME_HEADER_2_B 'B' // 0x42
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#define FRAME_HEADER_2_C 'C' // 0x43
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#define DIST_MAX_CM 5000
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#define OUT_OF_RANGE_ADD_CM 100
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bool AP_RangeFinder_JRE_Serial::get_reading(float &reading_m)
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{
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// uart instance check
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if (uart == nullptr) {
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return false; // not update
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}
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uint16_t valid_count = 0; // number of valid readings
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uint16_t invalid_count = 0; // number of invalid readings
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float sum = 0;
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// max distance the sensor can reliably measure - read from parameters
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const int16_t distance_cm_max = max_distance_cm();
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// buffer read
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const ssize_t num_read = uart->read(read_buff, ARRAY_SIZE(read_buff));
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for (read_buff_idx = 0; read_buff_idx < num_read; read_buff_idx++) {
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if (data_buff_idx == 0) { // header first byte check
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// header data search
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if (read_buff[read_buff_idx] == FRAME_HEADER_1) {
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data_buff[0] = FRAME_HEADER_1;
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data_buff_idx = 1; // next data_buff
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}
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} else if (data_buff_idx == 1) { // header second byte check
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data_buff[1] = read_buff[read_buff_idx];
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data_buff_idx = 2; // next data_buff
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switch (read_buff[read_buff_idx]) {
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case FRAME_HEADER_2_A:
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data_buff_len = 16;
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break;
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case FRAME_HEADER_2_B:
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data_buff_len = 32;
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break;
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case FRAME_HEADER_2_C:
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data_buff_len = 48;
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break;
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default:
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data_buff_idx = 0; // data index clear
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break;
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}
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} else { // data set
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data_buff[data_buff_idx++] = read_buff[read_buff_idx];
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if (data_buff_idx >= data_buff_len) { // 1 data set complete
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// crc check
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uint16_t crc = crc16_ccitt_r(data_buff, data_buff_len - 2, 0xffff, 0xffff);
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if ((HIGHBYTE(crc) == data_buff[data_buff_len-1]) && (LOWBYTE(crc) == data_buff[data_buff_len-2])) {
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// status check
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if (data_buff[data_buff_len-3] & 0x02) { // NTRK
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invalid_count++;
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} else { // TRK
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reading_m = (data_buff[4] * 256 + data_buff[5]) * 0.01f;
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sum += reading_m;
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valid_count++;
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}
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}
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data_buff_idx = 0; // data index clear
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}
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}
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}
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// return average of all valid readings
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if (valid_count > 0) {
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no_signal = false;
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reading_m = sum / valid_count;
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return true;
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}
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// all readings were invalid so return out-of-range-high value
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if (invalid_count > 0) {
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no_signal = true;
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reading_m = MIN(MAX(DIST_MAX_CM, distance_cm_max + OUT_OF_RANGE_ADD_CM), UINT16_MAX) * 0.01f;
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return true;
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}
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return false;
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}
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#endif // AP_RANGEFINDER_JRE_SERIAL_ENABLED
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