mirror of https://github.com/ArduPilot/ardupilot
246 lines
8.1 KiB
C++
246 lines
8.1 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_HAL/AP_HAL.h>
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#include "AP_RangeFinder_LeddarOne.h"
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#include <AP_SerialManager/AP_SerialManager.h>
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extern const AP_HAL::HAL& hal;
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/*
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The constructor also initialises the rangefinder. Note that this
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constructor is not called until detect() returns true, so we
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already know that we should setup the rangefinder
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*/
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AP_RangeFinder_LeddarOne::AP_RangeFinder_LeddarOne(RangeFinder::RangeFinder_State &_state,
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AP_RangeFinder_Params &_params,
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AP_SerialManager &serial_manager,
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uint8_t serial_instance) :
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AP_RangeFinder_Backend(_state, _params)
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{
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uart = serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance);
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if (uart != nullptr) {
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uart->begin(serial_manager.find_baudrate(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance));
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}
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}
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/*
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detect if a LeddarOne rangefinder is connected. We'll detect by
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trying to take a reading on Serial. If we get a result the sensor is
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there.
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*/
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bool AP_RangeFinder_LeddarOne::detect(AP_SerialManager &serial_manager, uint8_t serial_instance)
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{
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return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Rangefinder, serial_instance) != nullptr;
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}
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// read - return last value measured by sensor
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bool AP_RangeFinder_LeddarOne::get_reading(uint16_t &reading_cm)
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{
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uint8_t number_detections;
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LeddarOne_Status leddarone_status;
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if (uart == nullptr) {
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return false;
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}
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switch (modbus_status) {
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case LEDDARONE_MODBUS_STATE_INIT: {
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uint8_t index = 0;
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// clear read buffer
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uint32_t nbytes = uart->available();
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while (nbytes-- > 0) {
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uart->read();
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if (++index > LEDDARONE_SERIAL_PORT_MAX) {
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// LEDDARONE_STATE_ERR_SERIAL_PORT
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return false;
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}
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}
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// clear buffer and buffer_len
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memset(read_buffer, 0, sizeof(read_buffer));
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read_len = 0;
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modbus_status = LEDDARONE_MODBUS_STATE_PRE_SEND_REQUEST;
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}
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// fall through to next state LEDDARONE_MODBUS_STATE_PRE_SEND_REQUEST
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// immediately
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FALLTHROUGH;
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case LEDDARONE_MODBUS_STATE_PRE_SEND_REQUEST:
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// send a request message for Modbus function 4
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uart->write(send_request_buffer, sizeof(send_request_buffer));
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modbus_status = LEDDARONE_MODBUS_STATE_SENT_REQUEST;
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last_sending_request_ms = AP_HAL::millis();
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FALLTHROUGH;
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case LEDDARONE_MODBUS_STATE_SENT_REQUEST:
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if (uart->available()) {
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// change mod_bus status to read available buffer
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modbus_status = LEDDARONE_MODBUS_STATE_AVAILABLE;
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last_available_ms = AP_HAL::millis();
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} else {
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if (AP_HAL::millis() - last_sending_request_ms > 200) {
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// reset mod_bus status to read new buffer
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// if read_len is zero, send request without initialize
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modbus_status = (read_len == 0) ? LEDDARONE_MODBUS_STATE_PRE_SEND_REQUEST : LEDDARONE_MODBUS_STATE_INIT;
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}
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}
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break;
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case LEDDARONE_MODBUS_STATE_AVAILABLE:
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// parse a response message, set number_detections, detections and sum_distance
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leddarone_status = parse_response(number_detections);
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if (leddarone_status == LEDDARONE_STATE_OK) {
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reading_cm = sum_distance / number_detections;
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// reset mod_bus status to read new buffer
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modbus_status = LEDDARONE_MODBUS_STATE_INIT;
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return true;
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}
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// if status is not reading buffer, reset mod_bus status to read new buffer
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else if (leddarone_status != LEDDARONE_STATE_READING_BUFFER || AP_HAL::millis() - last_available_ms > 200) {
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// if read_len is zero, send request without initialize
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modbus_status = (read_len == 0) ? LEDDARONE_MODBUS_STATE_PRE_SEND_REQUEST : LEDDARONE_MODBUS_STATE_INIT;
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}
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break;
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}
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return false;
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}
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/*
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update the state of the sensor
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*/
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void AP_RangeFinder_LeddarOne::update(void)
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{
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if (get_reading(state.distance_cm)) {
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// update range_valid state based on distance measured
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state.last_reading_ms = AP_HAL::millis();
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update_status();
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} else if (AP_HAL::millis() - state.last_reading_ms > 200) {
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set_status(RangeFinder::RangeFinder_NoData);
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}
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}
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/*
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CRC16
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CRC-16-IBM(x16+x15+x2+1)
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*/
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bool AP_RangeFinder_LeddarOne::CRC16(uint8_t *aBuffer, uint8_t aLength, bool aCheck)
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{
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uint16_t crc = 0xFFFF;
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for (uint32_t i=0; i<aLength; i++) {
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crc ^= aBuffer[i];
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for (uint32_t j=0; j<8; j++) {
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if (crc & 1) {
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crc = (crc >> 1) ^ 0xA001;
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} else {
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crc >>= 1;
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}
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}
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}
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uint8_t lCRCLo = LOWBYTE(crc);
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uint8_t lCRCHi = HIGHBYTE(crc);
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if (aCheck) {
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return (aBuffer[aLength] == lCRCLo) && (aBuffer[aLength+1] == lCRCHi);
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} else {
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aBuffer[aLength] = lCRCLo;
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aBuffer[aLength+1] = lCRCHi;
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return true;
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}
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}
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/*
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parse a response message from Modbus
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-----------------------------------------------
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[ read buffer packet ]
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-----------------------------------------------
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0: slave address (LEDDARONE_DEFAULT_ADDRESS)
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1: functions code
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2: ?
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3-4-5-6: timestamp
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7-8: internal temperature
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9: ?
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10: number of detections
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11-12: first distance
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13-14: first amplitude
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15-16: second distance
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17-18: second amplitude
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19-20: third distances
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21-22: third amplitude
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23: CRC Low
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24: CRC High
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-----------------------------------------------
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*/
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LeddarOne_Status AP_RangeFinder_LeddarOne::parse_response(uint8_t &number_detections)
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{
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uint8_t index;
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uint8_t index_offset = LEDDARONE_DETECTION_DATA_INDEX_OFFSET;
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// read serial
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uint32_t nbytes = uart->available();
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if (nbytes != 0) {
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for (index=read_len; index<nbytes+read_len; index++) {
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if (index >= LEDDARONE_READ_BUFFER_SIZE) {
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return LEDDARONE_STATE_ERR_BAD_RESPONSE;
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}
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read_buffer[index] = uart->read();
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}
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read_len += nbytes;
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if (read_len < LEDDARONE_READ_BUFFER_SIZE) {
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return LEDDARONE_STATE_READING_BUFFER;
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}
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}
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// lead_len is not 25 byte or function code is not 0x04
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if (read_len != LEDDARONE_READ_BUFFER_SIZE || read_buffer[1] != LEDDARONE_MODOBUS_FUNCTION_CODE) {
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return LEDDARONE_STATE_ERR_BAD_RESPONSE;
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}
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// CRC16
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if (!CRC16(read_buffer, read_len-2, true)) {
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return LEDDARONE_STATE_ERR_BAD_CRC;
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}
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// number of detections (index:10)
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number_detections = read_buffer[LEDDARONE_DETECTION_DATA_NUMBER_INDEX];
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// if the number of detection is over or zero , it is false
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if (number_detections > LEDDARONE_DETECTIONS_MAX || number_detections == 0) {
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return LEDDARONE_STATE_ERR_NUMBER_DETECTIONS;
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}
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memset(detections, 0, sizeof(detections));
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sum_distance = 0;
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for (index=0; index<number_detections; index++) {
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// construct data word from two bytes and convert mm to cm
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detections[index] = (static_cast<uint16_t>(read_buffer[index_offset])*256 + read_buffer[index_offset+1]) / 10;
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sum_distance += detections[index];
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// add index offset (4) to read next detection data
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index_offset += LEDDARONE_DETECTION_DATA_OFFSET;
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}
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return LEDDARONE_STATE_OK;
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}
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