Source code for adafruit_vl53l0x

# SPDX-FileCopyrightText: 2017 Tony DiCola for Adafruit Industries
#
# SPDX-License-Identifier: MIT

"""
`adafruit_vl53l0x`
====================================================

CircuitPython driver for the VL53L0X distance sensor.  This code is adapted
from the pololu driver here:
https://github.com/pololu/vl53l0x-arduino

See usage in the examples/vl53l0x_simpletest.py file.

* Author(s): Tony DiCola

Implementation Notes
--------------------

**Hardware:**

* Adafruit `VL53L0X Time of Flight Distance Sensor - ~30 to 1000mm
  <https://www.adafruit.com/product/3317>`_ (Product ID: 3317)

**Software and Dependencies:**

* Adafruit CircuitPython firmware for the ESP8622 and M0-based boards:
  https://github.com/adafruit/circuitpython/releases
* Adafruit's Bus Device library: https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
"""
import math
import time

import adafruit_bus_device.i2c_device as i2c_device
from micropython import const

__version__ = "0.0.0-auto.0"
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_VL53L0X.git"

# Configuration constants:
_SYSRANGE_START = const(0x00)
_SYSTEM_THRESH_HIGH = const(0x0C)
_SYSTEM_THRESH_LOW = const(0x0E)
_SYSTEM_SEQUENCE_CONFIG = const(0x01)
_SYSTEM_RANGE_CONFIG = const(0x09)
_SYSTEM_INTERMEASUREMENT_PERIOD = const(0x04)
_SYSTEM_INTERRUPT_CONFIG_GPIO = const(0x0A)
_GPIO_HV_MUX_ACTIVE_HIGH = const(0x84)
_SYSTEM_INTERRUPT_CLEAR = const(0x0B)
_RESULT_INTERRUPT_STATUS = const(0x13)
_RESULT_RANGE_STATUS = const(0x14)
_RESULT_CORE_AMBIENT_WINDOW_EVENTS_RTN = const(0xBC)
_RESULT_CORE_RANGING_TOTAL_EVENTS_RTN = const(0xC0)
_RESULT_CORE_AMBIENT_WINDOW_EVENTS_REF = const(0xD0)
_RESULT_CORE_RANGING_TOTAL_EVENTS_REF = const(0xD4)
_RESULT_PEAK_SIGNAL_RATE_REF = const(0xB6)
_ALGO_PART_TO_PART_RANGE_OFFSET_MM = const(0x28)
_I2C_SLAVE_DEVICE_ADDRESS = const(0x8A)
_MSRC_CONFIG_CONTROL = const(0x60)
_PRE_RANGE_CONFIG_MIN_SNR = const(0x27)
_PRE_RANGE_CONFIG_VALID_PHASE_LOW = const(0x56)
_PRE_RANGE_CONFIG_VALID_PHASE_HIGH = const(0x57)
_PRE_RANGE_MIN_COUNT_RATE_RTN_LIMIT = const(0x64)
_FINAL_RANGE_CONFIG_MIN_SNR = const(0x67)
_FINAL_RANGE_CONFIG_VALID_PHASE_LOW = const(0x47)
_FINAL_RANGE_CONFIG_VALID_PHASE_HIGH = const(0x48)
_FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT = const(0x44)
_PRE_RANGE_CONFIG_SIGMA_THRESH_HI = const(0x61)
_PRE_RANGE_CONFIG_SIGMA_THRESH_LO = const(0x62)
_PRE_RANGE_CONFIG_VCSEL_PERIOD = const(0x50)
_PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI = const(0x51)
_PRE_RANGE_CONFIG_TIMEOUT_MACROP_LO = const(0x52)
_SYSTEM_HISTOGRAM_BIN = const(0x81)
_HISTOGRAM_CONFIG_INITIAL_PHASE_SELECT = const(0x33)
_HISTOGRAM_CONFIG_READOUT_CTRL = const(0x55)
_FINAL_RANGE_CONFIG_VCSEL_PERIOD = const(0x70)
_FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI = const(0x71)
_FINAL_RANGE_CONFIG_TIMEOUT_MACROP_LO = const(0x72)
_CROSSTALK_COMPENSATION_PEAK_RATE_MCPS = const(0x20)
_MSRC_CONFIG_TIMEOUT_MACROP = const(0x46)
_SOFT_RESET_GO2_SOFT_RESET_N = const(0xBF)
_IDENTIFICATION_MODEL_ID = const(0xC0)
_IDENTIFICATION_REVISION_ID = const(0xC2)
_OSC_CALIBRATE_VAL = const(0xF8)
_GLOBAL_CONFIG_VCSEL_WIDTH = const(0x32)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_0 = const(0xB0)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_1 = const(0xB1)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_2 = const(0xB2)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_3 = const(0xB3)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_4 = const(0xB4)
_GLOBAL_CONFIG_SPAD_ENABLES_REF_5 = const(0xB5)
_GLOBAL_CONFIG_REF_EN_START_SELECT = const(0xB6)
_DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD = const(0x4E)
_DYNAMIC_SPAD_REF_EN_START_OFFSET = const(0x4F)
_POWER_MANAGEMENT_GO1_POWER_FORCE = const(0x80)
_VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV = const(0x89)
_ALGO_PHASECAL_LIM = const(0x30)
_ALGO_PHASECAL_CONFIG_TIMEOUT = const(0x30)
_VCSEL_PERIOD_PRE_RANGE = const(0)
_VCSEL_PERIOD_FINAL_RANGE = const(1)


def _decode_timeout(val):
    # format: "(LSByte * 2^MSByte) + 1"
    return float(val & 0xFF) * math.pow(2.0, ((val & 0xFF00) >> 8)) + 1


def _encode_timeout(timeout_mclks):
    # format: "(LSByte * 2^MSByte) + 1"
    timeout_mclks = int(timeout_mclks) & 0xFFFF
    ls_byte = 0
    ms_byte = 0
    if timeout_mclks > 0:
        ls_byte = timeout_mclks - 1
        while ls_byte > 255:
            ls_byte >>= 1
            ms_byte += 1
        return ((ms_byte << 8) | (ls_byte & 0xFF)) & 0xFFFF
    return 0


def _timeout_mclks_to_microseconds(timeout_period_mclks, vcsel_period_pclks):
    macro_period_ns = ((2304 * (vcsel_period_pclks) * 1655) + 500) // 1000
    return ((timeout_period_mclks * macro_period_ns) + (macro_period_ns // 2)) // 1000


def _timeout_microseconds_to_mclks(timeout_period_us, vcsel_period_pclks):
    macro_period_ns = ((2304 * (vcsel_period_pclks) * 1655) + 500) // 1000
    return ((timeout_period_us * 1000) + (macro_period_ns // 2)) // macro_period_ns


[docs]class VL53L0X: """Driver for the VL53L0X distance sensor.""" # Class-level buffer for reading and writing data with the sensor. # This reduces memory allocations but means the code is not re-entrant or # thread safe! _BUFFER = bytearray(3) def __init__(self, i2c, address=41, io_timeout_s=0): # pylint: disable=too-many-statements self._i2c = i2c self._device = i2c_device.I2CDevice(i2c, address) self.io_timeout_s = io_timeout_s # Check identification registers for expected values. # From section 3.2 of the datasheet. if ( self._read_u8(0xC0) != 0xEE or self._read_u8(0xC1) != 0xAA or self._read_u8(0xC2) != 0x10 ): raise RuntimeError( "Failed to find expected ID register values. Check wiring!" ) # Initialize access to the sensor. This is based on the logic from: # https://github.com/pololu/vl53l0x-arduino/blob/master/VL53L0X.cpp # Set I2C standard mode. for pair in ((0x88, 0x00), (0x80, 0x01), (0xFF, 0x01), (0x00, 0x00)): self._write_u8(pair[0], pair[1]) self._stop_variable = self._read_u8(0x91) for pair in ((0x00, 0x01), (0xFF, 0x00), (0x80, 0x00)): self._write_u8(pair[0], pair[1]) # disable SIGNAL_RATE_MSRC (bit 1) and SIGNAL_RATE_PRE_RANGE (bit 4) # limit checks config_control = self._read_u8(_MSRC_CONFIG_CONTROL) | 0x12 self._write_u8(_MSRC_CONFIG_CONTROL, config_control) # set final range signal rate limit to 0.25 MCPS (million counts per # second) self.signal_rate_limit = 0.25 self._write_u8(_SYSTEM_SEQUENCE_CONFIG, 0xFF) spad_count, spad_is_aperture = self._get_spad_info() # The SPAD map (RefGoodSpadMap) is read by # VL53L0X_get_info_from_device() in the API, but the same data seems to # be more easily readable from GLOBAL_CONFIG_SPAD_ENABLES_REF_0 through # _6, so read it from there. ref_spad_map = bytearray(7) ref_spad_map[0] = _GLOBAL_CONFIG_SPAD_ENABLES_REF_0 with self._device: self._device.write(ref_spad_map, end=1) self._device.readinto(ref_spad_map, start=1) for pair in ( (0xFF, 0x01), (_DYNAMIC_SPAD_REF_EN_START_OFFSET, 0x00), (_DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD, 0x2C), (0xFF, 0x00), (_GLOBAL_CONFIG_REF_EN_START_SELECT, 0xB4), ): self._write_u8(pair[0], pair[1]) first_spad_to_enable = 12 if spad_is_aperture else 0 spads_enabled = 0 for i in range(48): if i < first_spad_to_enable or spads_enabled == spad_count: # This bit is lower than the first one that should be enabled, # or (reference_spad_count) bits have already been enabled, so # zero this bit. ref_spad_map[1 + (i // 8)] &= ~(1 << (i % 8)) elif (ref_spad_map[1 + (i // 8)] >> (i % 8)) & 0x1 > 0: spads_enabled += 1 with self._device: self._device.write(ref_spad_map) for pair in ( (0xFF, 0x01), (0x00, 0x00), (0xFF, 0x00), (0x09, 0x00), (0x10, 0x00), (0x11, 0x00), (0x24, 0x01), (0x25, 0xFF), (0x75, 0x00), (0xFF, 0x01), (0x4E, 0x2C), (0x48, 0x00), (0x30, 0x20), (0xFF, 0x00), (0x30, 0x09), (0x54, 0x00), (0x31, 0x04), (0x32, 0x03), (0x40, 0x83), (0x46, 0x25), (0x60, 0x00), (0x27, 0x00), (0x50, 0x06), (0x51, 0x00), (0x52, 0x96), (0x56, 0x08), (0x57, 0x30), (0x61, 0x00), (0x62, 0x00), (0x64, 0x00), (0x65, 0x00), (0x66, 0xA0), (0xFF, 0x01), (0x22, 0x32), (0x47, 0x14), (0x49, 0xFF), (0x4A, 0x00), (0xFF, 0x00), (0x7A, 0x0A), (0x7B, 0x00), (0x78, 0x21), (0xFF, 0x01), (0x23, 0x34), (0x42, 0x00), (0x44, 0xFF), (0x45, 0x26), (0x46, 0x05), (0x40, 0x40), (0x0E, 0x06), (0x20, 0x1A), (0x43, 0x40), (0xFF, 0x00), (0x34, 0x03), (0x35, 0x44), (0xFF, 0x01), (0x31, 0x04), (0x4B, 0x09), (0x4C, 0x05), (0x4D, 0x04), (0xFF, 0x00), (0x44, 0x00), (0x45, 0x20), (0x47, 0x08), (0x48, 0x28), (0x67, 0x00), (0x70, 0x04), (0x71, 0x01), (0x72, 0xFE), (0x76, 0x00), (0x77, 0x00), (0xFF, 0x01), (0x0D, 0x01), (0xFF, 0x00), (0x80, 0x01), (0x01, 0xF8), (0xFF, 0x01), (0x8E, 0x01), (0x00, 0x01), (0xFF, 0x00), (0x80, 0x00), ): self._write_u8(pair[0], pair[1]) self._write_u8(_SYSTEM_INTERRUPT_CONFIG_GPIO, 0x04) gpio_hv_mux_active_high = self._read_u8(_GPIO_HV_MUX_ACTIVE_HIGH) self._write_u8( _GPIO_HV_MUX_ACTIVE_HIGH, gpio_hv_mux_active_high & ~0x10 ) # active low self._write_u8(_SYSTEM_INTERRUPT_CLEAR, 0x01) self._measurement_timing_budget_us = self.measurement_timing_budget self._write_u8(_SYSTEM_SEQUENCE_CONFIG, 0xE8) self.measurement_timing_budget = self._measurement_timing_budget_us self._write_u8(_SYSTEM_SEQUENCE_CONFIG, 0x01) self._perform_single_ref_calibration(0x40) self._write_u8(_SYSTEM_SEQUENCE_CONFIG, 0x02) self._perform_single_ref_calibration(0x00) # "restore the previous Sequence Config" self._write_u8(_SYSTEM_SEQUENCE_CONFIG, 0xE8) def _read_u8(self, address): # Read an 8-bit unsigned value from the specified 8-bit address. with self._device: self._BUFFER[0] = address & 0xFF self._device.write(self._BUFFER, end=1) self._device.readinto(self._BUFFER, end=1) return self._BUFFER[0] def _read_u16(self, address): # Read a 16-bit BE unsigned value from the specified 8-bit address. with self._device: self._BUFFER[0] = address & 0xFF self._device.write(self._BUFFER, end=1) self._device.readinto(self._BUFFER) return (self._BUFFER[0] << 8) | self._BUFFER[1] def _write_u8(self, address, val): # Write an 8-bit unsigned value to the specified 8-bit address. with self._device: self._BUFFER[0] = address & 0xFF self._BUFFER[1] = val & 0xFF self._device.write(self._BUFFER, end=2) def _write_u16(self, address, val): # Write a 16-bit BE unsigned value to the specified 8-bit address. with self._device: self._BUFFER[0] = address & 0xFF self._BUFFER[1] = (val >> 8) & 0xFF self._BUFFER[2] = val & 0xFF self._device.write(self._BUFFER) def _get_spad_info(self): # Get reference SPAD count and type, returned as a 2-tuple of # count and boolean is_aperture. Based on code from: # https://github.com/pololu/vl53l0x-arduino/blob/master/VL53L0X.cpp for pair in ((0x80, 0x01), (0xFF, 0x01), (0x00, 0x00), (0xFF, 0x06)): self._write_u8(pair[0], pair[1]) self._write_u8(0x83, self._read_u8(0x83) | 0x04) for pair in ( (0xFF, 0x07), (0x81, 0x01), (0x80, 0x01), (0x94, 0x6B), (0x83, 0x00), ): self._write_u8(pair[0], pair[1]) start = time.monotonic() while self._read_u8(0x83) == 0x00: if ( self.io_timeout_s > 0 and (time.monotonic() - start) >= self.io_timeout_s ): raise RuntimeError("Timeout waiting for VL53L0X!") self._write_u8(0x83, 0x01) tmp = self._read_u8(0x92) count = tmp & 0x7F is_aperture = ((tmp >> 7) & 0x01) == 1 for pair in ((0x81, 0x00), (0xFF, 0x06)): self._write_u8(pair[0], pair[1]) self._write_u8(0x83, self._read_u8(0x83) & ~0x04) for pair in ((0xFF, 0x01), (0x00, 0x01), (0xFF, 0x00), (0x80, 0x00)): self._write_u8(pair[0], pair[1]) return (count, is_aperture) def _perform_single_ref_calibration(self, vhv_init_byte): # based on VL53L0X_perform_single_ref_calibration() from ST API. self._write_u8(_SYSRANGE_START, 0x01 | vhv_init_byte & 0xFF) start = time.monotonic() while (self._read_u8(_RESULT_INTERRUPT_STATUS) & 0x07) == 0: if ( self.io_timeout_s > 0 and (time.monotonic() - start) >= self.io_timeout_s ): raise RuntimeError("Timeout waiting for VL53L0X!") self._write_u8(_SYSTEM_INTERRUPT_CLEAR, 0x01) self._write_u8(_SYSRANGE_START, 0x00) def _get_vcsel_pulse_period(self, vcsel_period_type): # pylint: disable=no-else-return # Disable should be removed when refactor can be tested if vcsel_period_type == _VCSEL_PERIOD_PRE_RANGE: val = self._read_u8(_PRE_RANGE_CONFIG_VCSEL_PERIOD) return (((val) + 1) & 0xFF) << 1 elif vcsel_period_type == _VCSEL_PERIOD_FINAL_RANGE: val = self._read_u8(_FINAL_RANGE_CONFIG_VCSEL_PERIOD) return (((val) + 1) & 0xFF) << 1 return 255 def _get_sequence_step_enables(self): # based on VL53L0X_GetSequenceStepEnables() from ST API sequence_config = self._read_u8(_SYSTEM_SEQUENCE_CONFIG) tcc = (sequence_config >> 4) & 0x1 > 0 dss = (sequence_config >> 3) & 0x1 > 0 msrc = (sequence_config >> 2) & 0x1 > 0 pre_range = (sequence_config >> 6) & 0x1 > 0 final_range = (sequence_config >> 7) & 0x1 > 0 return (tcc, dss, msrc, pre_range, final_range) def _get_sequence_step_timeouts(self, pre_range): # based on get_sequence_step_timeout() from ST API but modified by # pololu here: # https://github.com/pololu/vl53l0x-arduino/blob/master/VL53L0X.cpp pre_range_vcsel_period_pclks = self._get_vcsel_pulse_period( _VCSEL_PERIOD_PRE_RANGE ) msrc_dss_tcc_mclks = (self._read_u8(_MSRC_CONFIG_TIMEOUT_MACROP) + 1) & 0xFF msrc_dss_tcc_us = _timeout_mclks_to_microseconds( msrc_dss_tcc_mclks, pre_range_vcsel_period_pclks ) pre_range_mclks = _decode_timeout( self._read_u16(_PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI) ) pre_range_us = _timeout_mclks_to_microseconds( pre_range_mclks, pre_range_vcsel_period_pclks ) final_range_vcsel_period_pclks = self._get_vcsel_pulse_period( _VCSEL_PERIOD_FINAL_RANGE ) final_range_mclks = _decode_timeout( self._read_u16(_FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI) ) if pre_range: final_range_mclks -= pre_range_mclks final_range_us = _timeout_mclks_to_microseconds( final_range_mclks, final_range_vcsel_period_pclks ) return ( msrc_dss_tcc_us, pre_range_us, final_range_us, final_range_vcsel_period_pclks, pre_range_mclks, ) @property def signal_rate_limit(self): """The signal rate limit in mega counts per second.""" val = self._read_u16(_FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT) # Return value converted from 16-bit 9.7 fixed point to float. return val / (1 << 7) @signal_rate_limit.setter def signal_rate_limit(self, val): assert 0.0 <= val <= 511.99 # Convert to 16-bit 9.7 fixed point value from a float. val = int(val * (1 << 7)) self._write_u16(_FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT, val) @property def measurement_timing_budget(self): """The measurement timing budget in microseconds.""" budget_us = 1910 + 960 # Start overhead + end overhead. tcc, dss, msrc, pre_range, final_range = self._get_sequence_step_enables() step_timeouts = self._get_sequence_step_timeouts(pre_range) msrc_dss_tcc_us, pre_range_us, final_range_us, _, _ = step_timeouts if tcc: budget_us += msrc_dss_tcc_us + 590 if dss: budget_us += 2 * (msrc_dss_tcc_us + 690) elif msrc: budget_us += msrc_dss_tcc_us + 660 if pre_range: budget_us += pre_range_us + 660 if final_range: budget_us += final_range_us + 550 self._measurement_timing_budget_us = budget_us return budget_us @measurement_timing_budget.setter def measurement_timing_budget(self, budget_us): # pylint: disable=too-many-locals assert budget_us >= 20000 used_budget_us = 1320 + 960 # Start (diff from get) + end overhead tcc, dss, msrc, pre_range, final_range = self._get_sequence_step_enables() step_timeouts = self._get_sequence_step_timeouts(pre_range) msrc_dss_tcc_us, pre_range_us, _ = step_timeouts[:3] final_range_vcsel_period_pclks, pre_range_mclks = step_timeouts[3:] if tcc: used_budget_us += msrc_dss_tcc_us + 590 if dss: used_budget_us += 2 * (msrc_dss_tcc_us + 690) elif msrc: used_budget_us += msrc_dss_tcc_us + 660 if pre_range: used_budget_us += pre_range_us + 660 if final_range: used_budget_us += 550 # "Note that the final range timeout is determined by the timing # budget and the sum of all other timeouts within the sequence. # If there is no room for the final range timeout, then an error # will be set. Otherwise the remaining time will be applied to # the final range." if used_budget_us > budget_us: raise ValueError("Requested timeout too big.") final_range_timeout_us = budget_us - used_budget_us final_range_timeout_mclks = _timeout_microseconds_to_mclks( final_range_timeout_us, final_range_vcsel_period_pclks ) if pre_range: final_range_timeout_mclks += pre_range_mclks self._write_u16( _FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI, _encode_timeout(final_range_timeout_mclks), ) self._measurement_timing_budget_us = budget_us @property def range(self): """Perform a single reading of the range for an object in front of the sensor and return the distance in millimeters. """ # Adapted from readRangeSingleMillimeters & # readRangeContinuousMillimeters in pololu code at: # https://github.com/pololu/vl53l0x-arduino/blob/master/VL53L0X.cpp for pair in ( (0x80, 0x01), (0xFF, 0x01), (0x00, 0x00), (0x91, self._stop_variable), (0x00, 0x01), (0xFF, 0x00), (0x80, 0x00), (_SYSRANGE_START, 0x01), ): self._write_u8(pair[0], pair[1]) start = time.monotonic() while (self._read_u8(_SYSRANGE_START) & 0x01) > 0: if ( self.io_timeout_s > 0 and (time.monotonic() - start) >= self.io_timeout_s ): raise RuntimeError("Timeout waiting for VL53L0X!") start = time.monotonic() while (self._read_u8(_RESULT_INTERRUPT_STATUS) & 0x07) == 0: if ( self.io_timeout_s > 0 and (time.monotonic() - start) >= self.io_timeout_s ): raise RuntimeError("Timeout waiting for VL53L0X!") # assumptions: Linearity Corrective Gain is 1000 (default) # fractional ranging is not enabled range_mm = self._read_u16(_RESULT_RANGE_STATUS + 10) self._write_u8(_SYSTEM_INTERRUPT_CLEAR, 0x01) return range_mm
[docs] def set_address(self, new_address): """Set a new I2C address to the instantaited object. This is only called when using multiple VL53L0X sensors on the same I2C bus (SDA & SCL pins). See also the `example <examples.html#multiple-vl53l0x-on-same-i2c-bus>`_ for proper usage. :param int new_address: The 7-bit `int` that is to be assigned to the VL53L0X sensor. The address that is assigned should NOT be already in use by another device on the I2C bus. .. important:: To properly set the address to an individual VL53L0X sensor, you must first ensure that all other VL53L0X sensors (using the default address of ``0x29``) on the same I2C bus are in their off state by pulling the "SHDN" pins LOW. When the "SHDN" pin is pulled HIGH again the default I2C address is ``0x29``. """ self._write_u8(_I2C_SLAVE_DEVICE_ADDRESS, new_address & 0x7F) self._device = i2c_device.I2CDevice(self._i2c, new_address)