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VL53L0X.cpp
- Committer:
- shalutha
- Date:
- 2019-10-01
- Revision:
- 0:69ce6d469c71
File content as of revision 0:69ce6d469c71:
// Most of the functionality of this library is based on the VL53L0X API // provided by ST (STSW-IMG005), and some of the explanatory comments are quoted // or paraphrased from the API source code, API user manual (UM2039), and the // VL53L0X datasheet. #include <memory> #include <VL53L0X.h> // Defines ///////////////////////////////////////////////////////////////////// // The Arduino two-wire interface uses a 7-bit number for the address, // and sets the last bit correctly based on reads and writes #define ADDRESS_DEFAULT (0b0101001 << 1) // Record the current time to check an upcoming timeout against #define startTimeout() (timeout_start_ms = millis()) // Check if timeout is enabled (set to nonzero value) and has expired #define checkTimeoutExpired() (io_timeout > 0 && ((uint16_t)millis() - timeout_start_ms) > io_timeout) // Decode VCSEL (vertical cavity surface emitting laser) pulse period in PCLKs // from register value // based on VL53L0X_decode_vcsel_period() #define decodeVcselPeriod(reg_val) (((reg_val) + 1) << 1) // Encode VCSEL pulse period register value from period in PCLKs // based on VL53L0X_encode_vcsel_period() #define encodeVcselPeriod(period_pclks) (((period_pclks) >> 1) - 1) // Calculate macro period in *nanoseconds* from VCSEL period in PCLKs // based on VL53L0X_calc_macro_period_ps() // PLL_period_ps = 1655; macro_period_vclks = 2304 #define calcMacroPeriod(vcsel_period_pclks) ((((uint32_t)2304 * (vcsel_period_pclks) * 1655) + 500) / 1000) // Transmission status (https://www.arduino.cc/en/Reference/WireEndTransmission) #define ERR_OK 0 #define ERR_NACK_ADDR 2 // received NACK on transmit of address #define ERR_NACK_DATA 3 // received NACK on transmit of data #define ERR_OTHER 4 #define millis() timer->read_ms() // Constructors //////////////////////////////////////////////////////////////// VL53L0X::VL53L0X(I2C* i2c, Timer* timer) : address(ADDRESS_DEFAULT) , io_timeout(0) // no timeout , did_timeout(false) , i2c(i2c) , timer(timer) { } // Public Methods ////////////////////////////////////////////////////////////// void VL53L0X::setAddress(uint8_t new_addr) { writeReg(I2C_SLAVE_DEVICE_ADDRESS, new_addr & 0x7F); address = new_addr << 1; } // Initialize sensor using sequence based on VL53L0X_DataInit(), // VL53L0X_StaticInit(), and VL53L0X_PerformRefCalibration(). // This function does not perform reference SPAD calibration // (VL53L0X_PerformRefSpadManagement()), since the API user manual says that it // is performed by ST on the bare modules; it seems like that should work well // enough unless a cover glass is added. // If io_2v8 (optional) is true or not given, the sensor is configured for 2V8 // mode. bool VL53L0X::init(bool io_2v8) { // VL53L0X_DataInit() begin // sensor uses 1V8 mode for I/O by default; switch to 2V8 mode if necessary if (io_2v8) { writeReg(VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV, readReg(VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV) | 0x01); // set bit 0 } // "Set I2C standard mode" writeReg(0x88, 0x00); writeReg(0x80, 0x01); writeReg(0xFF, 0x01); writeReg(0x00, 0x00); stop_variable = readReg(0x91); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x00); // disable SIGNAL_RATE_MSRC (bit 1) and SIGNAL_RATE_PRE_RANGE (bit 4) limit checks writeReg(MSRC_CONFIG_CONTROL, readReg(MSRC_CONFIG_CONTROL) | 0x12); // set final range signal rate limit to 0.25 MCPS (million counts per second) setSignalRateLimit(0.25); writeReg(SYSTEM_SEQUENCE_CONFIG, 0xFF); // VL53L0X_DataInit() end // VL53L0X_StaticInit() begin uint8_t spad_count; bool spad_type_is_aperture; if (!getSpadInfo(&spad_count, &spad_type_is_aperture)) { return false; } // 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 uint8_t ref_spad_map[6]; readMulti(GLOBAL_CONFIG_SPAD_ENABLES_REF_0, ref_spad_map, 6); // -- VL53L0X_set_reference_spads() begin (assume NVM values are valid) writeReg(0xFF, 0x01); writeReg(DYNAMIC_SPAD_REF_EN_START_OFFSET, 0x00); writeReg(DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD, 0x2C); writeReg(0xFF, 0x00); writeReg(GLOBAL_CONFIG_REF_EN_START_SELECT, 0xB4); uint8_t first_spad_to_enable = spad_type_is_aperture ? 12 : 0; // 12 is the first aperture spad uint8_t spads_enabled = 0; for (uint8_t i = 0; i < 48; i++) { if (i < first_spad_to_enable || 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[i / 8] &= ~(1 << (i % 8)); } else if ((ref_spad_map[i / 8] >> (i % 8)) & 0x1) { spads_enabled++; } } writeMulti(GLOBAL_CONFIG_SPAD_ENABLES_REF_0, ref_spad_map, 6); // -- VL53L0X_set_reference_spads() end // -- VL53L0X_load_tuning_settings() begin // DefaultTuningSettings from vl53l0x_tuning.h writeReg(0xFF, 0x01); writeReg(0x00, 0x00); writeReg(0xFF, 0x00); writeReg(0x09, 0x00); writeReg(0x10, 0x00); writeReg(0x11, 0x00); writeReg(0x24, 0x01); writeReg(0x25, 0xFF); writeReg(0x75, 0x00); writeReg(0xFF, 0x01); writeReg(0x4E, 0x2C); writeReg(0x48, 0x00); writeReg(0x30, 0x20); writeReg(0xFF, 0x00); writeReg(0x30, 0x09); writeReg(0x54, 0x00); writeReg(0x31, 0x04); writeReg(0x32, 0x03); writeReg(0x40, 0x83); writeReg(0x46, 0x25); writeReg(0x60, 0x00); writeReg(0x27, 0x00); writeReg(0x50, 0x06); writeReg(0x51, 0x00); writeReg(0x52, 0x96); writeReg(0x56, 0x08); writeReg(0x57, 0x30); writeReg(0x61, 0x00); writeReg(0x62, 0x00); writeReg(0x64, 0x00); writeReg(0x65, 0x00); writeReg(0x66, 0xA0); writeReg(0xFF, 0x01); writeReg(0x22, 0x32); writeReg(0x47, 0x14); writeReg(0x49, 0xFF); writeReg(0x4A, 0x00); writeReg(0xFF, 0x00); writeReg(0x7A, 0x0A); writeReg(0x7B, 0x00); writeReg(0x78, 0x21); writeReg(0xFF, 0x01); writeReg(0x23, 0x34); writeReg(0x42, 0x00); writeReg(0x44, 0xFF); writeReg(0x45, 0x26); writeReg(0x46, 0x05); writeReg(0x40, 0x40); writeReg(0x0E, 0x06); writeReg(0x20, 0x1A); writeReg(0x43, 0x40); writeReg(0xFF, 0x00); writeReg(0x34, 0x03); writeReg(0x35, 0x44); writeReg(0xFF, 0x01); writeReg(0x31, 0x04); writeReg(0x4B, 0x09); writeReg(0x4C, 0x05); writeReg(0x4D, 0x04); writeReg(0xFF, 0x00); writeReg(0x44, 0x00); writeReg(0x45, 0x20); writeReg(0x47, 0x08); writeReg(0x48, 0x28); writeReg(0x67, 0x00); writeReg(0x70, 0x04); writeReg(0x71, 0x01); writeReg(0x72, 0xFE); writeReg(0x76, 0x00); writeReg(0x77, 0x00); writeReg(0xFF, 0x01); writeReg(0x0D, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x01); writeReg(0x01, 0xF8); writeReg(0xFF, 0x01); writeReg(0x8E, 0x01); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x00); // -- VL53L0X_load_tuning_settings() end // "Set interrupt config to new sample ready" // -- VL53L0X_SetGpioConfig() begin writeReg(SYSTEM_INTERRUPT_CONFIG_GPIO, 0x04); writeReg(GPIO_HV_MUX_ACTIVE_HIGH, readReg(GPIO_HV_MUX_ACTIVE_HIGH) & ~0x10); // active low writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01); // -- VL53L0X_SetGpioConfig() end measurement_timing_budget_us = getMeasurementTimingBudget(); // "Disable MSRC and TCC by default" // MSRC = Minimum Signal Rate Check // TCC = Target CentreCheck // -- VL53L0X_SetSequenceStepEnable() begin writeReg(SYSTEM_SEQUENCE_CONFIG, 0xE8); // -- VL53L0X_SetSequenceStepEnable() end // "Recalculate timing budget" setMeasurementTimingBudget(measurement_timing_budget_us); // VL53L0X_StaticInit() end // VL53L0X_PerformRefCalibration() begin (VL53L0X_perform_ref_calibration()) // -- VL53L0X_perform_vhv_calibration() begin writeReg(SYSTEM_SEQUENCE_CONFIG, 0x01); if (!performSingleRefCalibration(0x40)) { return false; } // -- VL53L0X_perform_vhv_calibration() end // -- VL53L0X_perform_phase_calibration() begin writeReg(SYSTEM_SEQUENCE_CONFIG, 0x02); if (!performSingleRefCalibration(0x00)) { return false; } // -- VL53L0X_perform_phase_calibration() end // "restore the previous Sequence Config" writeReg(SYSTEM_SEQUENCE_CONFIG, 0xE8); // VL53L0X_PerformRefCalibration() end return true; } // Write an 8-bit register void VL53L0X::writeReg(uint8_t reg, uint8_t value) { char data[] = { reg, value }; if (i2c->write(address, data, 2)) { last_status = ERR_OTHER; } else { last_status = ERR_OK; } } // Write a 16-bit register void VL53L0X::writeReg16Bit(uint8_t reg, uint16_t value) { char data[] = { reg, static_cast<char>((value >> 8) & 0xFF), // value high byte static_cast<char>(value & 0xFF) // value low byte }; if (i2c->write(address, data, 3)) { last_status = ERR_OTHER; } else { last_status = ERR_OK; } } // Write a 32-bit register void VL53L0X::writeReg32Bit(uint8_t reg, uint32_t value) { char data[] = { reg, static_cast<char>((value >> 24) & 0xFF), // value highest byte static_cast<char>((value >> 16) & 0xFF), static_cast<char>((value >> 8) & 0xFF), static_cast<char>(value & 0xFF) // value lowest byte }; if (i2c->write(address, data, 5)) { last_status = ERR_OTHER; } else { last_status = ERR_OK; } } // Read an 8-bit register uint8_t VL53L0X::readReg(uint8_t reg) { uint8_t value; if (i2c->write(address, reinterpret_cast<char *>(®), 1)) { last_status = ERR_NACK_ADDR; return 0; } if (i2c->read(address, reinterpret_cast<char *>(&value), 1)) { last_status = ERR_NACK_DATA; return 0; } last_status = ERR_OK; return value; } // Read a 16-bit register uint16_t VL53L0X::readReg16Bit(uint8_t reg) { uint16_t value; uint8_t data[2]; if (i2c->write(address, reinterpret_cast<char *>(®), 1)) { last_status = ERR_NACK_ADDR; return 0; } if (i2c->read(address, reinterpret_cast<char *>(data), 2)) { last_status = ERR_NACK_DATA; return 0; } last_status = ERR_OK; value = static_cast<uint16_t>(data[0] << 8); // value high byte value |= data[1]; // value low byte return value; } // Read a 32-bit register uint32_t VL53L0X::readReg32Bit(uint8_t reg) { uint32_t value; uint8_t data[4]; if (i2c->write(address, reinterpret_cast<char *>(®), 1)) { last_status = ERR_NACK_ADDR; return 0; } if (i2c->read(address, reinterpret_cast<char *>(data), 4)) { last_status = ERR_NACK_DATA; return 0; } last_status = ERR_OK; value = static_cast<uint32_t>(data[0] << 24); // value highest byte value |= static_cast<uint32_t>(data[1] << 16); value |= static_cast<uint32_t>(data[2] << 8); value |= data[3]; // value lowest byte return value; } // Write an arbitrary number of bytes from the given array to the sensor, // starting at the given register void VL53L0X::writeMulti(uint8_t reg, uint8_t const * src, uint8_t count) { if (i2c->write(address, reinterpret_cast<char *>(®), 1, true)) { last_status = ERR_NACK_ADDR; return; } if (i2c->write(address, const_cast<char *>( reinterpret_cast<const char *>(src)), count)) { last_status = ERR_NACK_DATA; return; } last_status = ERR_OK; } // Read an arbitrary number of bytes from the sensor, starting at the given // register, into the given array void VL53L0X::readMulti(uint8_t reg, uint8_t * dst, uint8_t count) { if (i2c->write(address, reinterpret_cast<char *>(®), 1)) { last_status = ERR_NACK_ADDR; return; } if (i2c->read(address, reinterpret_cast<char *>(dst), count)) { last_status = ERR_NACK_DATA; return; } last_status = ERR_OK; } // Set the return signal rate limit check value in units of MCPS (mega counts // per second). "This represents the amplitude of the signal reflected from the // target and detected by the device"; setting this limit presumably determines // the minimum measurement necessary for the sensor to report a valid reading. // Setting a lower limit increases the potential range of the sensor but also // seems to increase the likelihood of getting an inaccurate reading because of // unwanted reflections from objects other than the intended target. // Defaults to 0.25 MCPS as initialized by the ST API and this library. bool VL53L0X::setSignalRateLimit(float limit_Mcps) { if (limit_Mcps < 0 || limit_Mcps > 511.99) { return false; } // Q9.7 fixed point format (9 integer bits, 7 fractional bits) writeReg16Bit(FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT, limit_Mcps * (1 << 7)); return true; } // Get the return signal rate limit check value in MCPS float VL53L0X::getSignalRateLimit(void) { return (float)readReg16Bit(FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT) / (1 << 7); } // Set the measurement timing budget in microseconds, which is the time allowed // for one measurement; the ST API and this library take care of splitting the // timing budget among the sub-steps in the ranging sequence. A longer timing // budget allows for more accurate measurements. Increasing the budget by a // factor of N decreases the range measurement standard deviation by a factor of // sqrt(N). Defaults to about 33 milliseconds; the minimum is 20 ms. // based on VL53L0X_set_measurement_timing_budget_micro_seconds() bool VL53L0X::setMeasurementTimingBudget(uint32_t budget_us) { SequenceStepEnables enables; SequenceStepTimeouts timeouts; uint16_t const StartOverhead = 1320; // note that this is different than the value in get_ uint16_t const EndOverhead = 960; uint16_t const MsrcOverhead = 660; uint16_t const TccOverhead = 590; uint16_t const DssOverhead = 690; uint16_t const PreRangeOverhead = 660; uint16_t const FinalRangeOverhead = 550; uint32_t const MinTimingBudget = 20000; if (budget_us < MinTimingBudget) { return false; } uint32_t used_budget_us = StartOverhead + EndOverhead; getSequenceStepEnables(&enables); getSequenceStepTimeouts(&enables, &timeouts); if (enables.tcc) { used_budget_us += (timeouts.msrc_dss_tcc_us + TccOverhead); } if (enables.dss) { used_budget_us += 2 * (timeouts.msrc_dss_tcc_us + DssOverhead); } else if (enables.msrc) { used_budget_us += (timeouts.msrc_dss_tcc_us + MsrcOverhead); } if (enables.pre_range) { used_budget_us += (timeouts.pre_range_us + PreRangeOverhead); } if (enables.final_range) { used_budget_us += FinalRangeOverhead; // "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) { // "Requested timeout too big." return false; } uint32_t final_range_timeout_us = budget_us - used_budget_us; // set_sequence_step_timeout() begin // (SequenceStepId == VL53L0X_SEQUENCESTEP_FINAL_RANGE) // "For the final range timeout, the pre-range timeout // must be added. To do this both final and pre-range // timeouts must be expressed in macro periods MClks // because they have different vcsel periods." uint16_t final_range_timeout_mclks = timeoutMicrosecondsToMclks(final_range_timeout_us, timeouts.final_range_vcsel_period_pclks); if (enables.pre_range) { final_range_timeout_mclks += timeouts.pre_range_mclks; } writeReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI, encodeTimeout(final_range_timeout_mclks)); // set_sequence_step_timeout() end measurement_timing_budget_us = budget_us; // store for internal reuse } return true; } // Get the measurement timing budget in microseconds // based on VL53L0X_get_measurement_timing_budget_micro_seconds() // in us uint32_t VL53L0X::getMeasurementTimingBudget(void) { SequenceStepEnables enables; SequenceStepTimeouts timeouts; uint16_t const StartOverhead = 1910; // note that this is different than the value in set_ uint16_t const EndOverhead = 960; uint16_t const MsrcOverhead = 660; uint16_t const TccOverhead = 590; uint16_t const DssOverhead = 690; uint16_t const PreRangeOverhead = 660; uint16_t const FinalRangeOverhead = 550; // "Start and end overhead times always present" uint32_t budget_us = StartOverhead + EndOverhead; getSequenceStepEnables(&enables); getSequenceStepTimeouts(&enables, &timeouts); if (enables.tcc) { budget_us += (timeouts.msrc_dss_tcc_us + TccOverhead); } if (enables.dss) { budget_us += 2 * (timeouts.msrc_dss_tcc_us + DssOverhead); } else if (enables.msrc) { budget_us += (timeouts.msrc_dss_tcc_us + MsrcOverhead); } if (enables.pre_range) { budget_us += (timeouts.pre_range_us + PreRangeOverhead); } if (enables.final_range) { budget_us += (timeouts.final_range_us + FinalRangeOverhead); } measurement_timing_budget_us = budget_us; // store for internal reuse return budget_us; } // Set the VCSEL (vertical cavity surface emitting laser) pulse period for the // given period type (pre-range or final range) to the given value in PCLKs. // Longer periods seem to increase the potential range of the sensor. // Valid values are (even numbers only): // pre: 12 to 18 (initialized default: 14) // final: 8 to 14 (initialized default: 10) // based on VL53L0X_set_vcsel_pulse_period() bool VL53L0X::setVcselPulsePeriod(vcselPeriodType type, uint8_t period_pclks) { uint8_t vcsel_period_reg = encodeVcselPeriod(period_pclks); SequenceStepEnables enables; SequenceStepTimeouts timeouts; getSequenceStepEnables(&enables); getSequenceStepTimeouts(&enables, &timeouts); // "Apply specific settings for the requested clock period" // "Re-calculate and apply timeouts, in macro periods" // "When the VCSEL period for the pre or final range is changed, // the corresponding timeout must be read from the device using // the current VCSEL period, then the new VCSEL period can be // applied. The timeout then must be written back to the device // using the new VCSEL period. // // For the MSRC timeout, the same applies - this timeout being // dependant on the pre-range vcsel period." if (type == VcselPeriodPreRange) { // "Set phase check limits" switch (period_pclks) { case 12: writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x18); break; case 14: writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x30); break; case 16: writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x40); break; case 18: writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x50); break; default: // invalid period return false; } writeReg(PRE_RANGE_CONFIG_VALID_PHASE_LOW, 0x08); // apply new VCSEL period writeReg(PRE_RANGE_CONFIG_VCSEL_PERIOD, vcsel_period_reg); // update timeouts // set_sequence_step_timeout() begin // (SequenceStepId == VL53L0X_SEQUENCESTEP_PRE_RANGE) uint16_t new_pre_range_timeout_mclks = timeoutMicrosecondsToMclks(timeouts.pre_range_us, period_pclks); writeReg16Bit(PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI, encodeTimeout(new_pre_range_timeout_mclks)); // set_sequence_step_timeout() end // set_sequence_step_timeout() begin // (SequenceStepId == VL53L0X_SEQUENCESTEP_MSRC) uint16_t new_msrc_timeout_mclks = timeoutMicrosecondsToMclks(timeouts.msrc_dss_tcc_us, period_pclks); writeReg(MSRC_CONFIG_TIMEOUT_MACROP, (new_msrc_timeout_mclks > 256) ? 255 : (new_msrc_timeout_mclks - 1)); // set_sequence_step_timeout() end } else if (type == VcselPeriodFinalRange) { switch (period_pclks) { case 8: writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x10); writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08); writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x02); writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x0C); writeReg(0xFF, 0x01); writeReg(ALGO_PHASECAL_LIM, 0x30); writeReg(0xFF, 0x00); break; case 10: writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x28); writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08); writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03); writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x09); writeReg(0xFF, 0x01); writeReg(ALGO_PHASECAL_LIM, 0x20); writeReg(0xFF, 0x00); break; case 12: writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x38); writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08); writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03); writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x08); writeReg(0xFF, 0x01); writeReg(ALGO_PHASECAL_LIM, 0x20); writeReg(0xFF, 0x00); break; case 14: writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x48); writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08); writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03); writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x07); writeReg(0xFF, 0x01); writeReg(ALGO_PHASECAL_LIM, 0x20); writeReg(0xFF, 0x00); break; default: // invalid period return false; } // apply new VCSEL period writeReg(FINAL_RANGE_CONFIG_VCSEL_PERIOD, vcsel_period_reg); // update timeouts // set_sequence_step_timeout() begin // (SequenceStepId == VL53L0X_SEQUENCESTEP_FINAL_RANGE) // "For the final range timeout, the pre-range timeout // must be added. To do this both final and pre-range // timeouts must be expressed in macro periods MClks // because they have different vcsel periods." uint16_t new_final_range_timeout_mclks = timeoutMicrosecondsToMclks(timeouts.final_range_us, period_pclks); if (enables.pre_range) { new_final_range_timeout_mclks += timeouts.pre_range_mclks; } writeReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI, encodeTimeout(new_final_range_timeout_mclks)); // set_sequence_step_timeout end } else { // invalid type return false; } // "Finally, the timing budget must be re-applied" setMeasurementTimingBudget(measurement_timing_budget_us); // "Perform the phase calibration. This is needed after changing on vcsel period." // VL53L0X_perform_phase_calibration() begin uint8_t sequence_config = readReg(SYSTEM_SEQUENCE_CONFIG); writeReg(SYSTEM_SEQUENCE_CONFIG, 0x02); performSingleRefCalibration(0x0); writeReg(SYSTEM_SEQUENCE_CONFIG, sequence_config); // VL53L0X_perform_phase_calibration() end return true; } // Get the VCSEL pulse period in PCLKs for the given period type. // based on VL53L0X_get_vcsel_pulse_period() uint8_t VL53L0X::getVcselPulsePeriod(vcselPeriodType type) { if (type == VcselPeriodPreRange) { return decodeVcselPeriod(readReg(PRE_RANGE_CONFIG_VCSEL_PERIOD)); } else if (type == VcselPeriodFinalRange) { return decodeVcselPeriod(readReg(FINAL_RANGE_CONFIG_VCSEL_PERIOD)); } else { return 255; } } // Start continuous ranging measurements. If period_ms (optional) is 0 or not // given, continuous back-to-back mode is used (the sensor takes measurements as // often as possible); otherwise, continuous timed mode is used, with the given // inter-measurement period in milliseconds determining how often the sensor // takes a measurement. // based on VL53L0X_StartMeasurement() void VL53L0X::startContinuous(uint32_t period_ms) { writeReg(0x80, 0x01); writeReg(0xFF, 0x01); writeReg(0x00, 0x00); writeReg(0x91, stop_variable); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x00); if (period_ms != 0) { // continuous timed mode // VL53L0X_SetInterMeasurementPeriodMilliSeconds() begin uint16_t osc_calibrate_val = readReg16Bit(OSC_CALIBRATE_VAL); if (osc_calibrate_val != 0) { period_ms *= osc_calibrate_val; } writeReg32Bit(SYSTEM_INTERMEASUREMENT_PERIOD, period_ms); // VL53L0X_SetInterMeasurementPeriodMilliSeconds() end writeReg(SYSRANGE_START, 0x04); // VL53L0X_REG_SYSRANGE_MODE_TIMED } else { // continuous back-to-back mode writeReg(SYSRANGE_START, 0x02); // VL53L0X_REG_SYSRANGE_MODE_BACKTOBACK } } // Stop continuous measurements // based on VL53L0X_StopMeasurement() void VL53L0X::stopContinuous(void) { writeReg(SYSRANGE_START, 0x01); // VL53L0X_REG_SYSRANGE_MODE_SINGLESHOT writeReg(0xFF, 0x01); writeReg(0x00, 0x00); writeReg(0x91, 0x00); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); } // Returns a range reading in millimeters when continuous mode is active // (readRangeSingleMillimeters() also calls this function after starting a // single-shot range measurement) uint16_t VL53L0X::readRangeContinuousMillimeters(void) { startTimeout(); while ((readReg(RESULT_INTERRUPT_STATUS) & 0x07) == 0) { if (checkTimeoutExpired()) { did_timeout = true; return 65535; } } // assumptions: Linearity Corrective Gain is 1000 (default); // fractional ranging is not enabled uint16_t range = readReg16Bit(RESULT_RANGE_STATUS + 10); writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01); return range; } // Performs a single-shot range measurement and returns the reading in // millimeters // based on VL53L0X_PerformSingleRangingMeasurement() uint16_t VL53L0X::readRangeSingleMillimeters(void) { writeReg(0x80, 0x01); writeReg(0xFF, 0x01); writeReg(0x00, 0x00); writeReg(0x91, stop_variable); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x00); writeReg(SYSRANGE_START, 0x01); // "Wait until start bit has been cleared" startTimeout(); while (readReg(SYSRANGE_START) & 0x01) { if (checkTimeoutExpired()) { did_timeout = true; return 65535; } } return readRangeContinuousMillimeters(); } // Did a timeout occur in one of the read functions since the last call to // timeoutOccurred()? bool VL53L0X::timeoutOccurred() { bool tmp = did_timeout; did_timeout = false; return tmp; } // Private Methods ///////////////////////////////////////////////////////////// // Get reference SPAD (single photon avalanche diode) count and type // based on VL53L0X_get_info_from_device(), // but only gets reference SPAD count and type bool VL53L0X::getSpadInfo(uint8_t * count, bool * type_is_aperture) { uint8_t tmp; writeReg(0x80, 0x01); writeReg(0xFF, 0x01); writeReg(0x00, 0x00); writeReg(0xFF, 0x06); writeReg(0x83, readReg(0x83) | 0x04); writeReg(0xFF, 0x07); writeReg(0x81, 0x01); writeReg(0x80, 0x01); writeReg(0x94, 0x6b); writeReg(0x83, 0x00); startTimeout(); while (readReg(0x83) == 0x00) { if (checkTimeoutExpired()) { return false; } } writeReg(0x83, 0x01); tmp = readReg(0x92); *count = tmp & 0x7f; *type_is_aperture = (tmp >> 7) & 0x01; writeReg(0x81, 0x00); writeReg(0xFF, 0x06); writeReg(0x83, readReg( 0x83 & ~0x04)); writeReg(0xFF, 0x01); writeReg(0x00, 0x01); writeReg(0xFF, 0x00); writeReg(0x80, 0x00); return true; } // Get sequence step enables // based on VL53L0X_GetSequenceStepEnables() void VL53L0X::getSequenceStepEnables(SequenceStepEnables * enables) { uint8_t sequence_config = readReg(SYSTEM_SEQUENCE_CONFIG); enables->tcc = (sequence_config >> 4) & 0x1; enables->dss = (sequence_config >> 3) & 0x1; enables->msrc = (sequence_config >> 2) & 0x1; enables->pre_range = (sequence_config >> 6) & 0x1; enables->final_range = (sequence_config >> 7) & 0x1; } // Get sequence step timeouts // based on get_sequence_step_timeout(), // but gets all timeouts instead of just the requested one, and also stores // intermediate values void VL53L0X::getSequenceStepTimeouts(SequenceStepEnables const * enables, SequenceStepTimeouts * timeouts) { timeouts->pre_range_vcsel_period_pclks = getVcselPulsePeriod(VcselPeriodPreRange); timeouts->msrc_dss_tcc_mclks = readReg(MSRC_CONFIG_TIMEOUT_MACROP) + 1; timeouts->msrc_dss_tcc_us = timeoutMclksToMicroseconds(timeouts->msrc_dss_tcc_mclks, timeouts->pre_range_vcsel_period_pclks); timeouts->pre_range_mclks = decodeTimeout(readReg16Bit(PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI)); timeouts->pre_range_us = timeoutMclksToMicroseconds(timeouts->pre_range_mclks, timeouts->pre_range_vcsel_period_pclks); timeouts->final_range_vcsel_period_pclks = getVcselPulsePeriod(VcselPeriodFinalRange); timeouts->final_range_mclks = decodeTimeout(readReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI)); if (enables->pre_range) { timeouts->final_range_mclks -= timeouts->pre_range_mclks; } timeouts->final_range_us = timeoutMclksToMicroseconds(timeouts->final_range_mclks, timeouts->final_range_vcsel_period_pclks); } // Decode sequence step timeout in MCLKs from register value // based on VL53L0X_decode_timeout() // Note: the original function returned a uint32_t, but the return value is // always stored in a uint16_t. uint16_t VL53L0X::decodeTimeout(uint16_t reg_val) { // format: "(LSByte * 2^MSByte) + 1" return (uint16_t)((reg_val & 0x00FF) << (uint16_t)((reg_val & 0xFF00) >> 8)) + 1; } // Encode sequence step timeout register value from timeout in MCLKs // based on VL53L0X_encode_timeout() // Note: the original function took a uint16_t, but the argument passed to it // is always a uint16_t. uint16_t VL53L0X::encodeTimeout(uint16_t timeout_mclks) { // format: "(LSByte * 2^MSByte) + 1" uint32_t ls_byte = 0; uint16_t ms_byte = 0; if (timeout_mclks > 0) { ls_byte = timeout_mclks - 1; while ((ls_byte & 0xFFFFFF00) > 0) { ls_byte >>= 1; ms_byte++; } return (ms_byte << 8) | (ls_byte & 0xFF); } else { return 0; } } // Convert sequence step timeout from MCLKs to microseconds with given VCSEL period in PCLKs // based on VL53L0X_calc_timeout_us() uint32_t VL53L0X::timeoutMclksToMicroseconds(uint16_t timeout_period_mclks, uint8_t vcsel_period_pclks) { uint32_t macro_period_ns = calcMacroPeriod(vcsel_period_pclks); return ((timeout_period_mclks * macro_period_ns) + (macro_period_ns / 2)) / 1000; } // Convert sequence step timeout from microseconds to MCLKs with given VCSEL period in PCLKs // based on VL53L0X_calc_timeout_mclks() uint32_t VL53L0X::timeoutMicrosecondsToMclks(uint32_t timeout_period_us, uint8_t vcsel_period_pclks) { uint32_t macro_period_ns = calcMacroPeriod(vcsel_period_pclks); return (((timeout_period_us * 1000) + (macro_period_ns / 2)) / macro_period_ns); } // based on VL53L0X_perform_single_ref_calibration() bool VL53L0X::performSingleRefCalibration(uint8_t vhv_init_byte) { writeReg(SYSRANGE_START, 0x01 | vhv_init_byte); // VL53L0X_REG_SYSRANGE_MODE_START_STOP startTimeout(); while ((readReg(RESULT_INTERRUPT_STATUS) & 0x07) == 0) { if (checkTimeoutExpired()) { return false; } } writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01); writeReg(SYSRANGE_START, 0x00); return true; }