ardupilot/libraries/AP_Beacon/AP_Beacon_Pozyx.cpp

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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_Beacon_Pozyx.h"
#include <ctype.h>
#include <stdio.h>
extern const AP_HAL::HAL& hal;
// return true if sensor is basically healthy (we are receiving data)
bool AP_Beacon_Pozyx::healthy()
{
// healthy if we have parsed a message within the past 300ms
return ((AP_HAL::millis() - last_update_ms) < AP_BEACON_TIMEOUT_MS);
}
// update the state of the sensor
void AP_Beacon_Pozyx::update(void)
{
if (uart == nullptr) {
return;
}
// read any available characters
int16_t nbytes = uart->available();
while (nbytes-- > 0) {
char c = uart->read();
switch (parse_state) {
default:
case ParseState_WaitingForHeader:
if (c == AP_BEACON_POZYX_HEADER) {
parse_state = ParseState_WaitingForMsgId;
linebuf_len = 0;
}
break;
case ParseState_WaitingForMsgId:
parse_msg_id = c;
switch (parse_msg_id) {
case AP_BEACON_POZYX_MSGID_BEACON_CONFIG:
case AP_BEACON_POZYX_MSGID_BEACON_DIST:
case AP_BEACON_POZYX_MSGID_POSITION:
parse_state = ParseState_WaitingForLen;
break;
default:
// invalid message id
parse_state = ParseState_WaitingForHeader;
break;
}
break;
case ParseState_WaitingForLen:
parse_msg_len = c;
if (parse_msg_len > AP_BEACON_POZYX_MSG_LEN_MAX) {
// invalid message length
parse_state = ParseState_WaitingForHeader;
} else {
parse_state = ParseState_WaitingForContents;
}
break;
case ParseState_WaitingForContents:
// add to buffer
linebuf[linebuf_len++] = c;
if ((linebuf_len == parse_msg_len) || (linebuf_len == sizeof(linebuf))) {
// process buffer
parse_buffer();
// reset state for next message
parse_state = ParseState_WaitingForHeader;
}
break;
}
}
}
// parse buffer
void AP_Beacon_Pozyx::parse_buffer()
{
// check crc
uint8_t checksum = 0;
checksum ^= parse_msg_id;
checksum ^= parse_msg_len;
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for (uint8_t i=0; i<linebuf_len; i++) {
checksum ^= linebuf[i];
}
// return if failed checksum check
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if (checksum != 0) {
return;
}
bool parsed = false;
switch (parse_msg_id) {
case AP_BEACON_POZYX_MSGID_BEACON_CONFIG:
{
uint8_t beacon_id = linebuf[0];
//uint8_t beacon_count = linebuf[1];
int32_t beacon_x = (uint32_t)linebuf[5] << 24 | (uint32_t)linebuf[4] << 16 | (uint32_t)linebuf[3] << 8 | (uint32_t)linebuf[2];
int32_t beacon_y = (uint32_t)linebuf[9] << 24 | (uint32_t)linebuf[8] << 16 | (uint32_t)linebuf[7] << 8 | (uint32_t)linebuf[6];
int32_t beacon_z = (uint32_t)linebuf[13] << 24 | (uint32_t)linebuf[12] << 16 | (uint32_t)linebuf[11] << 8 | (uint32_t)linebuf[10];
Vector3f beacon_pos(beacon_x / 1000.0f, beacon_y / 1000.0f, -beacon_z / 1000.0f);
if (beacon_pos.length() <= AP_BEACON_DISTANCE_MAX) {
set_beacon_position(beacon_id, beacon_pos);
parsed = true;
}
}
break;
case AP_BEACON_POZYX_MSGID_BEACON_DIST:
{
uint8_t beacon_id = linebuf[0];
uint32_t beacon_distance = (uint32_t)linebuf[4] << 24 | (uint32_t)linebuf[3] << 16 | (uint32_t)linebuf[2] << 8 | (uint32_t)linebuf[1];
float beacon_dist = beacon_distance/1000.0f;
if (beacon_dist <= AP_BEACON_DISTANCE_MAX) {
set_beacon_distance(beacon_id, beacon_dist);
parsed = true;
}
}
break;
case AP_BEACON_POZYX_MSGID_POSITION:
{
int32_t vehicle_x = (uint32_t)linebuf[3] << 24 | (uint32_t)linebuf[2] << 16 | (uint32_t)linebuf[1] << 8 | (uint32_t)linebuf[0];
int32_t vehicle_y = (uint32_t)linebuf[7] << 24 | (uint32_t)linebuf[6] << 16 | (uint32_t)linebuf[5] << 8 | (uint32_t)linebuf[4];
int32_t vehicle_z = (uint32_t)linebuf[11] << 24 | (uint32_t)linebuf[10] << 16 | (uint32_t)linebuf[9] << 8 | (uint32_t)linebuf[8];
int16_t position_error = (uint32_t)linebuf[13] << 8 | (uint32_t)linebuf[12];
Vector3f veh_pos(Vector3f(vehicle_x / 1000.0f, vehicle_y / 1000.0f, -vehicle_z / 1000.0f));
if (veh_pos.length() <= AP_BEACON_DISTANCE_MAX) {
set_vehicle_position(veh_pos, position_error);
parsed = true;
}
}
break;
default:
// unrecognised message id
break;
}
// record success
if (parsed) {
last_update_ms = AP_HAL::millis();
}
}