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AP_RangeFinder: initial support for the DFRobot07 lidar
- Only the distance and the temperature are extracted - 50 ms fixed reading interval - Only UART mode implemented
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217 changes: 217 additions & 0 deletions
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libraries/AP_RangeFinder/AP_RangeFinder_DFRobot_Lidar07.cpp
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| Original file line number | Diff line number | Diff line change |
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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/>. | ||
| */ | ||
|
|
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| #include "AP_HAL/utility/sparse-endian.h" | ||
| #include "AP_RangeFinder_config.h" | ||
| #include <endian.h> | ||
|
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| #if AP_RANGEFINDER_DFROBOT_LIDAR07_ENABLED | ||
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| #include "AP_RangeFinder_DFRobot_Lidar07.h" | ||
|
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| // DFRobot Lidar07 support driver | ||
| // Also sold as VSemi Atom | ||
| // Documentation: https://dfimg.dfrobot.com/nobody/wiki/1840a7b7b14e02f3566e0cef5b51e9ba.pdf | ||
| // https://wiki.dfrobot.com/TOF_IR_Distance_Sensor_0.2_12m_SKU_SEN0413 | ||
| // | ||
| // Current implementation only is limited to: | ||
| // - UART interface | ||
| // - Basic distance reading in continuous mode without an inbuilt filter | ||
|
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| #include <AP_HAL/AP_HAL.h> | ||
| #include <AP_Math/crc.h> | ||
| extern const AP_HAL::HAL& hal; | ||
|
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||
| #define LIDAR07_SOF_SENSOR (0xfa) | ||
| #define LIDAR07_SOF_CONTROLLER (0xf5) | ||
| #define LIDAR07_WRITE_MASK (0x80) | ||
| #define LIDAR07_REG_VERSION (0x43) | ||
| #define LIDAR07_REG_FILTER (0x59) | ||
| #define LIDAR07_REG_MEASUREMENT (0x60) | ||
| #define LIDAR07_REG_MODE (0x61) | ||
| #define LIDAR07_REG_INTERVAL (0x62) | ||
| #define LIDAR07_REG_ERROR (0x65) | ||
|
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| // the sensor supports rates up to 100 Hz | ||
| // use the lowest common rate between Copter and Plane: 20 Hz = 50 ms | ||
| #define LIDAR07_FRAME_INTERVAL_MS (50) | ||
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| // Invalidate the temperature and other readings after 2 measurement intervals | ||
| #define LIDAR07_DATA_EXPIRATION_MS (2*LIDAR07_FRAME_INTERVAL_MS) | ||
|
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| // Retry initialization if inactive for 30 seconds | ||
| #define LIDAR07_STALE_CONNECTION_MS (30*1000) | ||
|
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| // DFRobot's CRC32 implementation uses unreflected bit order | ||
| // apparently it's not the way CRC32 is used elsewhere so it makes sense to hide | ||
| // this utility under the define block | ||
| template <typename T> T reflect(const T& p) | ||
| { | ||
| // NOTE: straightforward bit reflection, can probably be optimized if used in high frequency code | ||
| T res = 0; | ||
| size_t bit_len = sizeof(T) * 8; | ||
| for (size_t i = 0; i < bit_len; i++) { | ||
| res |= bool(p & (1<<i)) << (bit_len - i - 1); | ||
| } | ||
| return res; | ||
| } | ||
|
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| uint32_t AP_RangeFinder_DFRobot_Lidar07::crc32_unreflected(uint8_t *buf, size_t n) | ||
| { | ||
| uint8_t ubuf[n]; | ||
| for (size_t i = 0; i < n; i++) | ||
| ubuf[i] = reflect<uint8_t>(buf[i]); | ||
| return reflect<uint32_t>(crc_crc32(0xffffffff, ubuf, n)); | ||
| } | ||
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| void AP_RangeFinder_DFRobot_Lidar07::prepare_command(uint8_t reg, uint32_t value) | ||
| { | ||
| _packet.start = LIDAR07_SOF_CONTROLLER; | ||
| _packet.reg = reg; | ||
| _packet.command.value = htole32(value); | ||
| _packet.command.checksum = htole32(crc32_unreflected(_buf, offsetof(Packet, command.checksum))); | ||
| _buf_pos = 0; | ||
| _writing = true; | ||
| _exp_reg = reg; | ||
| } | ||
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| bool AP_RangeFinder_DFRobot_Lidar07::get_reading(float &reading_m) | ||
| { | ||
| if (uart == nullptr) { | ||
| return false; | ||
| } | ||
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| // are we coming out of reset? | ||
| if (!_exp_reg) { | ||
| // no low noise filter to speed things up | ||
| prepare_command(LIDAR07_REG_FILTER | LIDAR07_WRITE_MASK, 0); | ||
| } | ||
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| // we have data to write, send what we can and return to get rescheduled | ||
| if (_writing) { | ||
| size_t left = offsetof(Packet, command.checksum) + sizeof(Packet::command.checksum) - _buf_pos; | ||
| size_t written = uart->write(&_buf[_buf_pos], left); | ||
| if (written < left) { | ||
| _buf_pos += written; | ||
| } else { | ||
| _buf_pos = 0; | ||
| _writing = false; | ||
| } | ||
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| return false; | ||
| } | ||
|
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| // invalidate connection and restart the setup if no data received in a while | ||
| if (AP_HAL::millis() - _last_read_ms > LIDAR07_STALE_CONNECTION_MS) { | ||
| _exp_reg = 0; | ||
| return false; | ||
| } | ||
|
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| // try reading a whole message from the serial | ||
| for (size_t i = 0; i < sizeof(_buf); i++) { | ||
| uint8_t c; | ||
| if (!uart->read(c)) { | ||
| break; | ||
| } | ||
| _last_read_ms = AP_HAL::millis(); | ||
|
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| // restart if we are somehow out of buffer | ||
| if (_buf_pos == sizeof(_buf)) { | ||
| _buf_pos = 0; | ||
| continue; | ||
| } | ||
|
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| // reject spurious fragments | ||
| if (_buf_pos == offsetof(Packet, start) && c != LIDAR07_SOF_SENSOR) { | ||
| continue; | ||
| } | ||
|
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| // reject things we aren't expecting to get | ||
| if (_buf_pos == offsetof(Packet, reg) && c != _exp_reg) { | ||
| _buf_pos = 0; | ||
| continue; | ||
| } | ||
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| _buf[_buf_pos++] = c; | ||
|
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| // pull the next byte if we haven't read the length yet | ||
| constexpr size_t data_offset = offsetof(Packet, len) + sizeof(Packet::len); | ||
| if (_buf_pos < data_offset) { | ||
| continue; | ||
| } | ||
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| // check if data length makes sense after we read all of the value | ||
| size_t exp_len = _exp_reg == LIDAR07_REG_MEASUREMENT? sizeof(Packet::measurement) : sizeof(Packet::responce); | ||
| if (_buf_pos == data_offset && le16toh(_packet.len) != exp_len) { | ||
| _buf_pos = 0; | ||
| continue; | ||
| } | ||
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| uint32_t crc32_offset = LIDAR07_REG_MEASUREMENT? offsetof(Packet, measurement.checksum) : offsetof(Packet, responce.checksum); | ||
| // looks like we have a full message, reset the counter and verify it | ||
| if (_buf_pos >= crc32_offset + sizeof(uint32_t)) { | ||
| _buf_pos = 0; | ||
|
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| // match the checksums | ||
| // incoming value on the wire is little endian | ||
| uint32_t message_crc32 = crc32_unreflected(_buf, crc32_offset); | ||
| uint32_t incoming_crc32 = LIDAR07_REG_MEASUREMENT? _packet.measurement.checksum : _packet.responce.checksum; | ||
| if (le32toh(incoming_crc32) == message_crc32) { | ||
| // We have a valid message, act in accordance to what we are expecting | ||
| // NOTE: we aren't actually checking that the responce values match what we demanded | ||
| switch (_exp_reg) { | ||
| case LIDAR07_REG_FILTER: | ||
| // continuous mode | ||
| prepare_command(LIDAR07_REG_MODE | LIDAR07_WRITE_MASK, 1); | ||
| return false; | ||
|
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| case LIDAR07_REG_MODE: | ||
| // frame rate | ||
| prepare_command(LIDAR07_REG_INTERVAL | LIDAR07_WRITE_MASK, LIDAR07_FRAME_INTERVAL_MS); | ||
| return false; | ||
|
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| case LIDAR07_REG_INTERVAL: | ||
| // start measuring | ||
| prepare_command(LIDAR07_REG_MEASUREMENT | LIDAR07_WRITE_MASK, 1); | ||
| return false; | ||
|
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| case LIDAR07_REG_MEASUREMENT: | ||
| // got a valid measurement, capture the fields | ||
| reading_m = le16toh(_packet.measurement.distance)/1000.0; | ||
| _temperature = le16toh(_packet.measurement.temperature)/100.0; | ||
|
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| // NOTE: other fields are unused right now | ||
| // we can probably figure out signal quality by light level/amplitude | ||
| return true; | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
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| // we've got nothing at this time | ||
| return false; | ||
| } | ||
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| bool AP_RangeFinder_DFRobot_Lidar07::get_temp(float &temp) const | ||
| { | ||
| if (AP_HAL::millis() - _last_read_ms > LIDAR07_DATA_EXPIRATION_MS) { | ||
| return false; | ||
| } | ||
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| temp = _temperature; | ||
| return true; | ||
| } | ||
|
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| #endif // AP_RANGEFINDER_DFROBOT_LIDAR07_ENABLED |
130 changes: 130 additions & 0 deletions
130
libraries/AP_RangeFinder/AP_RangeFinder_DFRobot_Lidar07.h
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,130 @@ | ||
| /* | ||
| 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/>. | ||
| */ | ||
|
|
||
| #pragma once | ||
|
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| #include "AP_RangeFinder_config.h" | ||
|
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| #if AP_RANGEFINDER_DFROBOT_LIDAR07_ENABLED | ||
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| #include "AP_RangeFinder.h" | ||
| #include "AP_RangeFinder_Backend_Serial.h" | ||
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| #include <AP_HAL/utility/sparse-endian.h> | ||
|
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| class AP_RangeFinder_DFRobot_Lidar07 : public AP_RangeFinder_Backend_Serial | ||
| { | ||
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| public: | ||
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| static AP_RangeFinder_Backend_Serial *create( | ||
| RangeFinder::RangeFinder_State &_state, | ||
| AP_RangeFinder_Params &_params) { | ||
| return NEW_NOTHROW AP_RangeFinder_DFRobot_Lidar07(_state, _params); | ||
| } | ||
|
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| protected: | ||
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| // 850 nm LED | ||
| MAV_DISTANCE_SENSOR _get_mav_distance_sensor_type() const override { | ||
| return MAV_DISTANCE_SENSOR_INFRARED; | ||
| } | ||
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| private: | ||
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| using AP_RangeFinder_Backend_Serial::AP_RangeFinder_Backend_Serial; | ||
|
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| // 115200 baud as per datasheet | ||
| uint32_t initial_baudrate(uint8_t serial_instance) const override { return 115200; } | ||
|
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| // get a distance reading | ||
| bool get_reading(float &reading_m) override; | ||
|
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| // get the latest encountered temperature | ||
| bool get_temp(float &temp) const override; | ||
|
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| // generate a command to the sensor and place it in the message buffer | ||
| void prepare_command(uint8_t reg, uint32_t value); | ||
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| // unreflected crc32 checksum with 0xffffffff initial value | ||
| static uint32_t crc32_unreflected(uint8_t *buf, size_t n); | ||
|
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| // last temperature seen | ||
| float _temperature; | ||
|
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| // packet structure | ||
| struct Packet | ||
| { | ||
| uint8_t start; | ||
| uint8_t reg; | ||
| union | ||
| { | ||
| // single value for packets sent to the sensor | ||
| struct | ||
| { | ||
| le32_t value; | ||
| le32_t checksum; | ||
| } command __attribute__((packed)); | ||
| // sensor responce | ||
| struct | ||
| { | ||
| // responces include a 16-bit data length although only 2 values are ever used | ||
| le16_t len; | ||
| union | ||
| { | ||
| // generic 32-bit reply | ||
| struct | ||
| { | ||
| le32_t value; | ||
| le32_t checksum; | ||
| } responce __attribute__((packed)); | ||
| // measurement response | ||
| struct | ||
| { | ||
| le16_t distance; | ||
| le16_t temperature; | ||
| le16_t amplitude; | ||
| le16_t ambient_light; | ||
| le64_t tof_phase; | ||
| le32_t checksum; | ||
| } measurement __attribute__((packed)); | ||
| }; | ||
| } __attribute__((packed)); | ||
| }; | ||
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| } __attribute__((packed)); | ||
|
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| // one message buffer | ||
| union | ||
| { | ||
| Packet _packet; | ||
| uint8_t _buf[sizeof(Packet)]; | ||
| }; | ||
|
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| // current buffer position | ||
| size_t _buf_pos = 0; | ||
|
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| // whether we are reading or writing | ||
| bool _writing = false; | ||
|
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| // expected message register | ||
| // 0 carries a special meaning of a state after reset | ||
| uint8_t _exp_reg = 0; | ||
|
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| // last time we've received a valid reading | ||
| uint32_t _last_read_ms = 0; | ||
| }; | ||
|
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| #endif // AP_RANGEFINDER_DFROBOT_LIDAR07_ENABLED |
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