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144 lines
4.5 KiB
144 lines
4.5 KiB
/* |
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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_Proximity_LightWareSerial.h" |
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#if HAL_PROXIMITY_ENABLED |
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#include <AP_Common/AP_Common.h> |
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#include <AP_HAL/AP_HAL.h> |
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#include <AP_HAL/utility/sparse-endian.h> |
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#include <AP_Math/crc.h> |
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#include <GCS_MAVLink/GCS.h> |
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extern const AP_HAL::HAL& hal; |
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#define PROXIMITY_LIGHTWARE_HEADER 0xAA |
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// send message to sensor |
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void AP_Proximity_LightWareSerial::send_message(uint8_t msgid, bool write, const uint8_t *payload, uint16_t payload_len) |
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{ |
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if ((_uart == nullptr) || (payload_len > PROXIMITY_LIGHTWARE_PAYLOAD_LEN_MAX)) { |
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return; |
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} |
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// check for sufficient space in outgoing buffer |
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if (_uart->txspace() < payload_len + 6U) { |
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return; |
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} |
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// write header |
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_uart->write((uint8_t)PROXIMITY_LIGHTWARE_HEADER); |
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uint16_t crc = crc_xmodem_update(0, PROXIMITY_LIGHTWARE_HEADER); |
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// write flags including payload length |
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const uint16_t flags = ((payload_len+1) << 6) | (write ? 0x01 : 0); |
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_uart->write(LOWBYTE(flags)); |
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crc = crc_xmodem_update(crc, LOWBYTE(flags)); |
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_uart->write(HIGHBYTE(flags)); |
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crc = crc_xmodem_update(crc, HIGHBYTE(flags)); |
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// msgid |
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_uart->write(msgid); |
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crc = crc_xmodem_update(crc, msgid); |
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// payload |
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if ((payload_len > 0) && (payload != nullptr)) { |
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for (uint16_t i = 0; i < payload_len; i++) { |
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_uart->write(payload[i]); |
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crc = crc_xmodem_update(crc, payload[i]); |
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} |
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} |
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// checksum |
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_uart->write(LOWBYTE(crc)); |
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_uart->write(HIGHBYTE(crc)); |
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} |
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// process one byte received on serial port |
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// returns true if a complete message has been received |
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// state is stored in _msg structure |
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bool AP_Proximity_LightWareSerial::parse_byte(uint8_t b) |
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{ |
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// check that payload buffer is large enough |
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static_assert(ARRAY_SIZE(_msg.payload) == PROXIMITY_LIGHTWARE_PAYLOAD_LEN_MAX, "AP_Proximity_LightWareSerial: check _msg.payload array size"); |
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// process byte depending upon current state |
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switch (_parse_state) { |
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case ParseState::HEADER: |
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if (b == PROXIMITY_LIGHTWARE_HEADER) { |
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_crc_expected = crc_xmodem_update(0, b); |
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_parse_state = ParseState::FLAGS_L; |
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} |
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break; |
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case ParseState::FLAGS_L: |
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_msg.flags_low = b; |
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_crc_expected = crc_xmodem_update(_crc_expected, b); |
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_parse_state = ParseState::FLAGS_H; |
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break; |
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case ParseState::FLAGS_H: |
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_msg.flags_high = b; |
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_crc_expected = crc_xmodem_update(_crc_expected, b); |
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_msg.payload_len = UINT16_VALUE(_msg.flags_high, _msg.flags_low) >> 6; |
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if ((_msg.payload_len == 0) || (_msg.payload_len > PROXIMITY_LIGHTWARE_PAYLOAD_LEN_MAX)) { |
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// invalid payload length, abandon message |
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_parse_state = ParseState::HEADER; |
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} else { |
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_parse_state = ParseState::MSG_ID; |
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} |
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break; |
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case ParseState::MSG_ID: |
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_msg.msgid = b; |
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_crc_expected = crc_xmodem_update(_crc_expected, b); |
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if (_msg.payload_len > 1) { |
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_parse_state = ParseState::PAYLOAD; |
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} else { |
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_parse_state = ParseState::CRC_L; |
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} |
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_payload_recv = 0; |
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break; |
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case ParseState::PAYLOAD: |
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if (_payload_recv < (_msg.payload_len - 1)) { |
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_msg.payload[_payload_recv] = b; |
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_payload_recv++; |
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_crc_expected = crc_xmodem_update(_crc_expected, b); |
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} |
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if (_payload_recv >= (_msg.payload_len - 1)) { |
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_parse_state = ParseState::CRC_L; |
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} |
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break; |
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case ParseState::CRC_L: |
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_msg.crc_low = b; |
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_parse_state = ParseState::CRC_H; |
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break; |
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case ParseState::CRC_H: |
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_parse_state = ParseState::HEADER; |
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_msg.crc_high = b; |
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if (_crc_expected == UINT16_VALUE(_msg.crc_high, _msg.crc_low)) { |
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return true; |
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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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#endif // HAL_PROXIMITY_ENABLED
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