CM8JL65.cpp

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#include "CM8JL65.hpp"

static constexpr unsigned char crc_msb_vector[] = {
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,
    0x00, 0xC1, 0x81, 0x40
};

static constexpr unsigned char crc_lsb_vector[] = {
    0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,
    0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,
    0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,
    0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,
    0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,
    0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,
    0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,
    0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,
    0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,
    0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,
    0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,
    0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,
    0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,
    0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,
    0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,
    0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,
    0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,
    0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,
    0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,
    0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,
    0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,
    0x41, 0x81, 0x80, 0x40
};

CM8JL65::CM8JL65(const char *port, uint8_t rotation) :
    ScheduledWorkItem(MODULE_NAME, px4::serial_port_to_wq(port)),
    _px4_rangefinder(0 /* TODO: device ids */, ORB_PRIO_DEFAULT, rotation)
{
    // Store the port name.
    strncpy(_port, port, sizeof(_port) - 1);

    // Enforce null termination.
    _port[sizeof(_port) - 1] = '\0';

    // Use conservative distance bounds, to make sure we don't fuse garbage data
    _px4_rangefinder.set_min_distance(0.2f);    // Datasheet: 0.17m
    _px4_rangefinder.set_max_distance(7.9f);    // Datasheet: 8.0m
    _px4_rangefinder.set_fov(0.0488692f);
}

CM8JL65::~CM8JL65()
{
    // Ensure we are truly inactive.
    stop();

    perf_free(_sample_perf);
    perf_free(_comms_errors);
}

uint16_t
CM8JL65::crc16_calc(const unsigned char *data_frame, uint8_t crc16_length)
{
    // compute CRC16 IBM 8005
    unsigned char crc_high_byte = 0xFF;
    unsigned char crc_low_byte = 0xFF;
    size_t index = 0;

    while (crc16_length--) {
        index = crc_low_byte ^ *(data_frame++);
        crc_low_byte = (unsigned char)(crc_high_byte ^ crc_msb_vector[index]);
        crc_high_byte = crc_lsb_vector[index];
    }

    uint16_t crc16 = (crc_high_byte << 8 | crc_low_byte);
    crc16 = (crc16 >> 8) | (crc16 << 8); // Convert endian

    return crc16;
}

int
CM8JL65::collect()
{
    perf_begin(_sample_perf);

    int bytes_processed = 0;
    int distance_mm = -1;
    int index = 0;

    bool crc_valid = false;

    // Read from the sensor UART buffer.
    const hrt_abstime timestamp_sample = hrt_absolute_time();
    int bytes_read = ::read(_file_descriptor, &_linebuf[0], sizeof(_linebuf));

    if (bytes_read > 0) {
        index = bytes_read - 6 ;

        while (index >= 0 && !crc_valid) {
            if (_linebuf[index] == START_FRAME_DIGIT1) {
                bytes_processed = index;

                while (bytes_processed < bytes_read && !crc_valid) {
                    if (data_parser(_linebuf[bytes_processed], _frame_data, _parse_state, _crc16, distance_mm) == PX4_OK) {
                        crc_valid = true;
                    }

                    bytes_processed++;
                }

                _parse_state = PARSE_STATE::WAITING_FRAME;
            }

            index--;
        }

    } else {
        PX4_INFO("read error: %d", bytes_read);
        perf_count(_comms_errors);
        perf_end(_sample_perf);
        return PX4_ERROR;
    }

    if (!crc_valid) {
        return -EAGAIN;
    }

    bytes_read = OK;

    const float current_distance = static_cast<float>(distance_mm) / 1000.0f;

    _px4_rangefinder.update(timestamp_sample, current_distance);

    perf_end(_sample_perf);

    return PX4_OK;
}

int
CM8JL65::data_parser(const uint8_t check_byte, uint8_t parserbuf[PARSER_BUF_LENGTH],
             PARSE_STATE &state, uint16_t &crc16, int &distance)
{
    switch (state) {
    case PARSE_STATE::WAITING_FRAME:
        if (check_byte == START_FRAME_DIGIT1) {
            state = PARSE_STATE::DIGIT_1;
        }

        break;

    case PARSE_STATE::DIGIT_1:
        if (check_byte == START_FRAME_DIGIT1) {
            state = PARSE_STATE::DIGIT_1;

        } else if (check_byte == START_FRAME_DIGIT2) {
            state = PARSE_STATE::DIGIT_2;

        } else {
            state = PARSE_STATE::WAITING_FRAME;
        }

        break;

    case PARSE_STATE::DIGIT_2:
        state = PARSE_STATE::MSB_DATA;
        parserbuf[DISTANCE_MSB_POS] = check_byte; // MSB Data
        break;

    case PARSE_STATE::MSB_DATA:
        state = PARSE_STATE::LSB_DATA;
        parserbuf[DISTANCE_LSB_POS] = check_byte; // LSB Data

        // Calculate CRC.
        crc16 = crc16_calc(parserbuf, PARSER_BUF_LENGTH);
        break;

    case PARSE_STATE::LSB_DATA:
        if (check_byte == (crc16 >> 8)) {
            state = PARSE_STATE::CHECKSUM;

        } else {
            state = PARSE_STATE::WAITING_FRAME;
        }

        break;

    case PARSE_STATE::CHECKSUM:
        // Here, reset state to `NOT-STARTED` no matter crc ok or not
        state = PARSE_STATE::WAITING_FRAME;

        if (check_byte == (crc16 & 0xFF)) {
            // printf("Checksum verified \n");
            distance = (parserbuf[DISTANCE_MSB_POS] << 8) | parserbuf[DISTANCE_LSB_POS];
            return PX4_OK;
        }

        break;
    }

    return PX4_ERROR;
}

int
CM8JL65::init()
{
    start();

    return PX4_OK;
}

int
CM8JL65::open_serial_port(const speed_t speed)
{
    // File descriptor initialized?
    if (_file_descriptor > 0) {
        // PX4_INFO("serial port already open");
        return PX4_OK;
    }

    // Configure port flags for read/write, non-controlling, non-blocking.
    int flags = (O_RDWR | O_NOCTTY | O_NONBLOCK);

    // Open the serial port.
    _file_descriptor = ::open(_port, flags);

    if (_file_descriptor < 0) {
        PX4_ERR("open failed (%i)", errno);
        return PX4_ERROR;
    }

    termios uart_config = {};

    // Store the current port configuration. attributes.
    tcgetattr(_file_descriptor, &uart_config);

    // Clear ONLCR flag (which appends a CR for every LF).
    uart_config.c_oflag &= ~ONLCR;

    // No parity, one stop bit.
    uart_config.c_cflag &= ~(CSTOPB | PARENB);

    // Set the input baud rate in the uart_config struct.
    int termios_state = cfsetispeed(&uart_config, speed);

    if (termios_state < 0) {
        PX4_ERR("CFG: %d ISPD", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    // Set the output baud rate in the uart_config struct.
    termios_state = cfsetospeed(&uart_config, speed);

    if (termios_state < 0) {
        PX4_ERR("CFG: %d OSPD", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    // Apply the modified port attributes.
    termios_state = tcsetattr(_file_descriptor, TCSANOW, &uart_config);

    if (termios_state < 0) {
        PX4_ERR("baud %d ATTR", termios_state);
        ::close(_file_descriptor);
        return PX4_ERROR;
    }

    PX4_INFO("successfully opened UART port %s", _port);
    return PX4_OK;
}

void
CM8JL65::print_info()
{
    perf_print_counter(_sample_perf);
    perf_print_counter(_comms_errors);

    _px4_rangefinder.print_status();
}

void
CM8JL65::Run()
{
    // Ensure the serial port is open.
    open_serial_port();

    // Perform collection.
    collect();
}

void
CM8JL65::start()
{
    // Schedule the driver at regular intervals.
    ScheduleOnInterval(CM8JL65_MEASURE_INTERVAL);

    PX4_INFO("driver started");
}

void
CM8JL65::stop()
{
    // Clear the work queue schedule.
    ScheduleClear();

    // Ensure the serial port is closed.
    ::close(_file_descriptor);
}