TOF/VL53L0X
使用するPSoC 5LPについて
（Cypresss社ページから画像を引用)
今回は、PSoC 5LP の評価キットCY8CKIT-059を使ってTOF(Time Of Flight)テクノロジーを使用したVL53L0Xを用いてレーザー距離測定にチャレンジしてみます。
この評価キットは完成品が1500円で買え、すぐ使用できるのが魅力です。 基板を途中で切り離してライターを別にできるのも便利ですね。
VL53L0X Ranging and Gesture Detection Sensorについて
STマイクロのページはこちら、http://www.st.com/ja/imaging-and-photonics-solutions/vl53l0x.html
このデバイスは4.4mmX2.4mmと非常に小さい上に裏面に端子がある表面実装デバイスですので通常のユニバーサル基板にハンダコテで付ける事ができません、またレーザーダイオードの標準駆動電圧が2.8V、絶対最大定格電源電圧が3.5Vなので一応3.3V系のコントローラーに直結しても動作しましたが寿命が短くなったり基本性能が出ない可能性もあります。 幸い2.8V⇄3.3Vのオペレーテイング電圧変換機能付きのアセンブリ済みモジュールが入手できるのでこれを利用します。
下記のスイッチサイエンスのページと、ストロベリーリナックスのページから購入できます。
スイッチサイエンス製（同社の販売ページから画像を引用）
ストロベリーリナックス製（同社の販売ページから画像を引用）
PSoCとの接続について
TOFモジュールには以下のピンがあります。
このモジュールはST Microのデータシートを確認しても、Registerの詳細が公開されておらず、
エバリュエーションキットに含まれるコードが提供するAPIを使用していくしかありません、
スイッチサイエンスのページにサンプルコードへのリンクが存在するので、これを元にPSoCで制御可能なものとします。
vl53l0x.h
#ifndef __VL53L0X_H__
#define __VL53L0X_H__
typedef enum { false, true } bool;
enum regAddr
{
SYSRANGE_START = 0x00,
SYSTEM_THRESH_HIGH = 0x0C,
SYSTEM_THRESH_LOW = 0x0E,
SYSTEM_SEQUENCE_CONFIG = 0x01,
SYSTEM_RANGE_CONFIG = 0x09,
SYSTEM_INTERMEASUREMENT_PERIOD = 0x04,
SYSTEM_INTERRUPT_CONFIG_GPIO = 0x0A,
GPIO_HV_MUX_ACTIVE_HIGH = 0x84,
SYSTEM_INTERRUPT_CLEAR = 0x0B,
RESULT_INTERRUPT_STATUS = 0x13,
RESULT_RANGE_STATUS = 0x14,
RESULT_CORE_AMBIENT_WINDOW_EVENTS_RTN = 0xBC,
RESULT_CORE_RANGING_TOTAL_EVENTS_RTN = 0xC0,
RESULT_CORE_AMBIENT_WINDOW_EVENTS_REF = 0xD0,
RESULT_CORE_RANGING_TOTAL_EVENTS_REF = 0xD4,
RESULT_PEAK_SIGNAL_RATE_REF = 0xB6,
ALGO_PART_TO_PART_RANGE_OFFSET_MM = 0x28,
I2C_SLAVE_DEVICE_ADDRESS = 0x8A,
MSRC_CONFIG_CONTROL = 0x60,
PRE_RANGE_CONFIG_MIN_SNR = 0x27,
PRE_RANGE_CONFIG_VALID_PHASE_LOW = 0x56,
PRE_RANGE_CONFIG_VALID_PHASE_HIGH = 0x57,
PRE_RANGE_MIN_COUNT_RATE_RTN_LIMIT = 0x64,
FINAL_RANGE_CONFIG_MIN_SNR = 0x67,
FINAL_RANGE_CONFIG_VALID_PHASE_LOW = 0x47,
FINAL_RANGE_CONFIG_VALID_PHASE_HIGH = 0x48,
FINAL_RANGE_CONFIG_MIN_COUNT_RATE_RTN_LIMIT = 0x44,
PRE_RANGE_CONFIG_SIGMA_THRESH_HI = 0x61,
PRE_RANGE_CONFIG_SIGMA_THRESH_LO = 0x62,
PRE_RANGE_CONFIG_VCSEL_PERIOD = 0x50,
PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI = 0x51,
PRE_RANGE_CONFIG_TIMEOUT_MACROP_LO = 0x52,
SYSTEM_HISTOGRAM_BIN = 0x81,
HISTOGRAM_CONFIG_INITIAL_PHASE_SELECT = 0x33,
HISTOGRAM_CONFIG_READOUT_CTRL = 0x55,
FINAL_RANGE_CONFIG_VCSEL_PERIOD = 0x70,
FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI = 0x71,
FINAL_RANGE_CONFIG_TIMEOUT_MACROP_LO = 0x72,
CROSSTALK_COMPENSATION_PEAK_RATE_MCPS = 0x20,
MSRC_CONFIG_TIMEOUT_MACROP = 0x46,
SOFT_RESET_GO2_SOFT_RESET_N = 0xBF,
IDENTIFICATION_MODEL_ID = 0xC0,
IDENTIFICATION_REVISION_ID = 0xC2,
OSC_CALIBRATE_VAL = 0xF8,
GLOBAL_CONFIG_VCSEL_WIDTH = 0x32,
GLOBAL_CONFIG_SPAD_ENABLES_REF_0 = 0xB0,
GLOBAL_CONFIG_SPAD_ENABLES_REF_1 = 0xB1,
GLOBAL_CONFIG_SPAD_ENABLES_REF_2 = 0xB2,
GLOBAL_CONFIG_SPAD_ENABLES_REF_3 = 0xB3,
GLOBAL_CONFIG_SPAD_ENABLES_REF_4 = 0xB4,
GLOBAL_CONFIG_SPAD_ENABLES_REF_5 = 0xB5,
GLOBAL_CONFIG_REF_EN_START_SELECT = 0xB6,
DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD = 0x4E,
DYNAMIC_SPAD_REF_EN_START_OFFSET = 0x4F,
POWER_MANAGEMENT_GO1_POWER_FORCE = 0x80,
VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV = 0x89,
ALGO_PHASECAL_LIM = 0x30,
ALGO_PHASECAL_CONFIG_TIMEOUT = 0x30,
};
typedef struct {
bool tcc, msrc, dss, pre_range, final_range;
} SequenceStepEnables;
typedef struct {
uint16_t pre_range_vcsel_period_pclks, final_range_vcsel_period_pclks;
uint16_t msrc_dss_tcc_mclks, pre_range_mclks, final_range_mclks;
uint32_t msrc_dss_tcc_us, pre_range_us, final_range_us;
} SequenceStepTimeouts;
typedef enum { VcselPeriodPreRange, VcselPeriodFinalRange }vcselPeriodType;
uint8_t last_status; // status of last I2C transmission
void vl53l0x_setAddress(uint8_t new_addr);
void vl53l0x_writeReg(uint8_t reg, uint8_t value);
void vl53l0x_writeReg16Bit(uint8_t reg, uint16_t value);
void vl53l0x_writeReg32Bit(uint8_t reg, uint32_t value);
uint8_t vl53l0x_readReg(uint8_t reg);
uint16_t vl53l0x_readReg16Bit(uint8_t reg);
uint32_t vl53l0x_readReg32Bit(uint8_t reg);
void vl53l0x_writeMulti(uint8_t reg, uint8_t const * src, uint8_t count);
void vl53l0x_readMulti(uint8_t reg, uint8_t * dst, uint8_t count);
bool vl53l0x_setSignalRateLimit(float limit_Mcps);
float vl53l0x_getSignalRateLimit(void);
bool vl53l0x_setMeasurementTimingBudget(uint32_t budget_us);
uint32_t vl53l0x_getMeasurementTimingBudget(void);
bool vl53l0x_setVcselPulsePeriod(vcselPeriodType type, uint8_t period_pclks);
uint8_t vl53l0x_getVcselPulsePeriod(vcselPeriodType type);
void vl53l0x_startContinuous(uint32_t period_ms);
void vl53l0x_stopContinuous(void);
uint16_t vl53l0x_readRangeContinuousMillimeters(void);
uint16_t vl53l0x_readRangeSingleMillimeters(void);
uint16_t timeout_start_ms = 0;
uint16_t io_timeout = 0;
void vl53l0x_setTimeout(uint16_t timeout) { io_timeout = timeout; }
uint16_t vl53l0x_getTimeout(void) { return io_timeout; }
bool vl53l0x_timeoutOccurred(void);
uint8_t address;
bool did_timeout;
uint8_t stop_variable; // read by init and used when starting measurement; is StopVariable field of VL53L0X_DevData_t structure in API
uint32_t measurement_timing_budget_us;
bool vl53l0x_getSpadInfo(uint8_t * count, bool * type_is_aperture);
void vl53l0x_getSequenceStepEnables(SequenceStepEnables * enables);
void vl53l0x_getSequenceStepTimeouts(SequenceStepEnables const * enables, SequenceStepTimeouts * timeouts);
bool vl53l0x_performSingleRefCalibration(uint8_t vhv_init_byte);
static uint16_t vl53l0x_decodeTimeout(uint16_t value);
static uint16_t vl53l0x_encodeTimeout(uint16_t timeout_mclks);
static uint32_t vl53l0x_timeoutMclksToMicroseconds(uint16_t timeout_period_mclks, uint8_t vcsel_period_pclks);
static uint32_t vl53l0x_timeoutMicrosecondsToMclks(uint32_t timeout_period_us, uint8_t vcsel_period_pclks);
uint8_t vl53l0x_getAddress(void) { return address; }
bool io_2v8 = true;
#endif
vl53l0x.c
#include "vl53l0x.h"
#include "project.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 0x29
// 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)
// Public Methods //////////////////////////////////////////////////////////////
void vl53l0x_setAddress(uint8_t new_addr)
{
vl53l0x_writeReg(I2C_SLAVE_DEVICE_ADDRESS, new_addr & 0x7F);
vl53l0x_address = new_addr;
}
// 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.
uint8_t vl53l0x_init(uint8_t io_2v8)
{
uint8_t spad_count;
uint8_t spad_type_is_aperture;
uint8_t ref_spad_map[6];
uint8_t first_spad_to_enable = spad_type_is_aperture ? 12 : 0; // 12 is the first aperture spad
uint8_t spads_enabled = 0;
uint8_t i;
vl53l0x_address = ADDRESS_DEFAULT;
io_timeout = 0; // no timeout
did_timeout = 0;
// sensor uses 1V8 mode for I/O by default; switch to 2V8 mode if necessary
if (io_2v8)
{
vl53l0x_writeReg(VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV,
vl53l0x_readReg(VHV_CONFIG_PAD_SCL_SDA__EXTSUP_HV) | 0x01); // set bit 0
}
// "Set I2C standard mode"
vl53l0x_writeReg(0x88, 0x00);
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
stop_variable = vl53l0x_readReg(0x91);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x00);
// disable SIGNAL_RATE_MSRC (bit 1) and SIGNAL_RATE_PRE_RANGE (bit 4) limit checks
vl53l0x_writeReg(MSRC_CONFIG_CONTROL, vl53l0x_readReg(MSRC_CONFIG_CONTROL) | 0x12);
// set final range signal rate limit to 0.25 MCPS (million counts per second)
vl53l0x_setSignalRateLimit(0.25);
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0xFF);
if (!vl53l0x_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
vl53l0x_readMulti(GLOBAL_CONFIG_SPAD_ENABLES_REF_0, ref_spad_map, 6);
// -- vl53l0x_set_reference_spads() begin (assume NVM values are valid)
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(DYNAMIC_SPAD_REF_EN_START_OFFSET, 0x00);
vl53l0x_writeReg(DYNAMIC_SPAD_NUM_REQUESTED_REF_SPAD, 0x2C);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(GLOBAL_CONFIG_REF_EN_START_SELECT, 0xB4);
for (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++;
}
}
vl53l0x_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
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x09, 0x00);
vl53l0x_writeReg(0x10, 0x00);
vl53l0x_writeReg(0x11, 0x00);
vl53l0x_writeReg(0x24, 0x01);
vl53l0x_writeReg(0x25, 0xFF);
vl53l0x_writeReg(0x75, 0x00);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x4E, 0x2C);
vl53l0x_writeReg(0x48, 0x00);
vl53l0x_writeReg(0x30, 0x20);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x30, 0x09);
vl53l0x_writeReg(0x54, 0x00);
vl53l0x_writeReg(0x31, 0x04);
vl53l0x_writeReg(0x32, 0x03);
vl53l0x_writeReg(0x40, 0x83);
vl53l0x_writeReg(0x46, 0x25);
vl53l0x_writeReg(0x60, 0x00);
vl53l0x_writeReg(0x27, 0x00);
vl53l0x_writeReg(0x50, 0x06);
vl53l0x_writeReg(0x51, 0x00);
vl53l0x_writeReg(0x52, 0x96);
vl53l0x_writeReg(0x56, 0x08);
vl53l0x_writeReg(0x57, 0x30);
vl53l0x_writeReg(0x61, 0x00);
vl53l0x_writeReg(0x62, 0x00);
vl53l0x_writeReg(0x64, 0x00);
vl53l0x_writeReg(0x65, 0x00);
vl53l0x_writeReg(0x66, 0xA0);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x22, 0x32);
vl53l0x_writeReg(0x47, 0x14);
vl53l0x_writeReg(0x49, 0xFF);
vl53l0x_writeReg(0x4A, 0x00);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x7A, 0x0A);
vl53l0x_writeReg(0x7B, 0x00);
vl53l0x_writeReg(0x78, 0x21);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x23, 0x34);
vl53l0x_writeReg(0x42, 0x00);
vl53l0x_writeReg(0x44, 0xFF);
vl53l0x_writeReg(0x45, 0x26);
vl53l0x_writeReg(0x46, 0x05);
vl53l0x_writeReg(0x40, 0x40);
vl53l0x_writeReg(0x0E, 0x06);
vl53l0x_writeReg(0x20, 0x1A);
vl53l0x_writeReg(0x43, 0x40);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x34, 0x03);
vl53l0x_writeReg(0x35, 0x44);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x31, 0x04);
vl53l0x_writeReg(0x4B, 0x09);
vl53l0x_writeReg(0x4C, 0x05);
vl53l0x_writeReg(0x4D, 0x04);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x44, 0x00);
vl53l0x_writeReg(0x45, 0x20);
vl53l0x_writeReg(0x47, 0x08);
vl53l0x_writeReg(0x48, 0x28);
vl53l0x_writeReg(0x67, 0x00);
vl53l0x_writeReg(0x70, 0x04);
vl53l0x_writeReg(0x71, 0x01);
vl53l0x_writeReg(0x72, 0xFE);
vl53l0x_writeReg(0x76, 0x00);
vl53l0x_writeReg(0x77, 0x00);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x0D, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0x01, 0xF8);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x8E, 0x01);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x00);
// -- vl53l0x_load_tuning_settings() end
// "Set interrupt config to new sample ready"
// -- vl53l0x_SetGpioConfig() begin
vl53l0x_writeReg(SYSTEM_INTERRUPT_CONFIG_GPIO, 0x04);
vl53l0x_writeReg(GPIO_HV_MUX_ACTIVE_HIGH, vl53l0x_readReg(GPIO_HV_MUX_ACTIVE_HIGH) & ~0x10); // active low
vl53l0x_writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01);
// -- vl53l0x_SetGpioConfig() end
measurement_timing_budget_us = vl53l0x_getMeasurementTimingBudget();
// "Disable MSRC and TCC by default"
// MSRC = Minimum Signal Rate Check
// TCC = Target CentreCheck
// -- vl53l0x_SetSequenceStepEnable() begin
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0xE8);
// -- vl53l0x_SetSequenceStepEnable() end
// "Recalculate timing budget"
vl53l0x_setMeasurementTimingBudget(measurement_timing_budget_us);
// vl53l0x_StaticInit() end
// vl53l0x_PerformRefCalibration() begin (vl53l0x_perform_ref_calibration())
// -- vl53l0x_perform_vhv_calibration() begin
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0x01);
if (!vl53l0x_performSingleRefCalibration(0x40)) { return FALSE; }
// -- vl53l0x_perform_vhv_calibration() end
// -- vl53l0x_perform_phase_calibration() begin
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0x02);
if (!vl53l0x_performSingleRefCalibration(0x00)) { return FALSE; }
// -- vl53l0x_perform_phase_calibration() end
// "restore the previous Sequence Config"
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0xE8);
// vl53l0x_PerformRefCalibration() end
setTimeout(500);
return TRUE;
}
void Delay(uint32 tick_delay)
{
uint32 tick_entry = gtick;
while(gtick - tick_entry < tick_delay);
}
// Write an 8-bit register
void vl53l0x_writeReg(uint8_t reg, uint8_t value)
{
uint8 status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterWriteByte(value);
Delay(1);
status = I2C_1_MasterSendStop();
}
// Write a 16-bit register
void vl53l0x_writeReg16Bit(uint8_t reg, uint16_t value)
{
uint8 status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterWriteByte((value >> 8) & 0xFF);
Delay(1);
status = I2C_1_MasterWriteByte( value & 0xFF);
Delay(1);
status = I2C_1_MasterSendStop();
}
// Write a 32-bit register
void vl53l0x_writeReg32Bit(uint8_t reg, uint32_t value)
{
uint8 status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterWriteByte((value >>24) & 0xFF);
Delay(1);
status = I2C_1_MasterWriteByte((value >>16) & 0xFF);
Delay(1);
status = I2C_1_MasterWriteByte((value >> 8) & 0xFF);
Delay(1);
status = I2C_1_MasterWriteByte( value & 0xFF);
Delay(1);
status = I2C_1_MasterSendStop();
}
// Read an 8-bit register
uint8_t vl53l0x_readReg(uint8_t reg)
{
uint8_t value = 0;
unsigned char data[4];
uint8 status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterSendStop();
Delay(1);
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_READ_XFER_MODE);
Delay(1);
value = I2C_1_MasterReadByte(I2C_1_ACK_DATA);
Delay(1);
status = I2C_1_MasterSendStop();
return value;
}
// Read a 16-bit register
uint16_t vl53l0x_readReg16Bit(uint8_t reg)
{
uint16_t value = 0;
uint8_t status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterSendStop();
Delay(1);
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_READ_XFER_MODE);
Delay(1);
value = I2C_1_MasterReadByte(I2C_1_ACK_DATA);
Delay(1);
value = value << 8;
value |= I2C_1_MasterReadByte(I2C_1_NAK_DATA) & 0xFF;
Delay(1);
status = I2C_1_MasterSendStop();
return value;
}
// Read a 32-bit register
uint32_t vl53l0x_readReg32Bit(uint8_t reg)
{
uint32_t value = 0;
uint8_t status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterSendStop();
Delay(1);
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_READ_XFER_MODE);
Delay(1);
value = I2C_1_MasterReadByte(I2C_1_ACK_DATA);
Delay(1);
value = value << 24;
value |= (I2C_1_MasterReadByte(I2C_1_ACK_DATA) & 0xFF) << 16;
Delay(1);
value |= (I2C_1_MasterReadByte(I2C_1_ACK_DATA) & 0xFF) << 8;
Delay(1);
value |= (I2C_1_MasterReadByte(I2C_1_NAK_DATA) & 0xFF);
Delay(1);
status = I2C_1_MasterSendStop();
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)
{
uint8_t status;
uint8_t i;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
for (i = 0; i < count; i++)
{
status = I2C_1_MasterWriteByte(*(src+i));
Delay(1);
}
status = I2C_1_MasterSendStop();
}
// 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)
{
uint8_t i;
uint8_t status;
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_WRITE_XFER_MODE);
Delay(1);
status = I2C_1_MasterWriteByte(reg);
Delay(1);
status = I2C_1_MasterSendStop();
Delay(1);
status = I2C_1_MasterSendStart(vl53l0x_address, I2C_1_READ_XFER_MODE);
Delay(1);
for (i = 0; i < count; i++ )
{
if ( i < (count-1) )
{
dst[i] = I2C_1_MasterReadByte(I2C_1_ACK_DATA);
}
else
{
dst[i] = I2C_1_MasterReadByte(I2C_1_NAK_DATA);
}
Delay(1);
}
status = I2C_1_MasterSendStop();
}
// 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.
uint8_t vl53l0x_setSignalRateLimit(float limit_Mcps)
{
if (limit_Mcps < 0.0 || limit_Mcps > 511.99) { return FALSE; }
// Q9.7 fixed point format (9 integer bits, 7 fractional bits)
vl53l0x_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)vl53l0x_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()
uint8_t vl53l0x_setMeasurementTimingBudget(uint32_t budget_us)
{
struct SequenceStepEnables enables;
struct 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;
uint32_t final_range_timeout_us ;
uint32_t used_budget_us ;
uint16_t final_range_timeout_mclks ;
if (budget_us < MinTimingBudget) { return FALSE; }
used_budget_us = StartOverhead + EndOverhead;
vl53l0x_getSequenceStepEnables(&enables);
vl53l0x_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;
}
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."
final_range_timeout_mclks =
vl53l0x_timeoutMicrosecondsToMclks(final_range_timeout_us,
timeouts.final_range_vcsel_period_pclks);
if (enables.pre_range)
{
final_range_timeout_mclks += timeouts.pre_range_mclks;
}
vl53l0x_writeReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI,
vl53l0x_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)
{
struct SequenceStepEnables enables;
struct 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;
vl53l0x_getSequenceStepEnables(&enables);
vl53l0x_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()
uint8_t vl53l0x_setVcselPulsePeriod(enum vcselPeriodType type, uint8_t period_pclks)
{
uint16_t new_pre_range_timeout_mclks ;
uint16_t new_msrc_timeout_mclks ;
uint8_t vcsel_period_reg = encodeVcselPeriod(period_pclks);
uint8_t sequence_config;
struct SequenceStepEnables enables;
struct SequenceStepTimeouts timeouts;
vl53l0x_getSequenceStepEnables(&enables);
vl53l0x_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:
vl53l0x_writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x18);
break;
case 14:
vl53l0x_writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x30);
break;
case 16:
vl53l0x_writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x40);
break;
case 18:
vl53l0x_writeReg(PRE_RANGE_CONFIG_VALID_PHASE_HIGH, 0x50);
break;
default:
// invalid period
return FALSE;
}
vl53l0x_writeReg(PRE_RANGE_CONFIG_VALID_PHASE_LOW, 0x08);
// apply new VCSEL period
vl53l0x_writeReg(PRE_RANGE_CONFIG_VCSEL_PERIOD, vcsel_period_reg);
// update timeouts
// set_sequence_step_timeout() begin
// (SequenceStepId == vl53l0x_SEQUENCESTEP_PRE_RANGE)
new_pre_range_timeout_mclks =
vl53l0x_timeoutMicrosecondsToMclks(timeouts.pre_range_us, period_pclks);
vl53l0x_writeReg16Bit(PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI,
vl53l0x_encodeTimeout(new_pre_range_timeout_mclks));
// set_sequence_step_timeout() end
// set_sequence_step_timeout() begin
// (SequenceStepId == vl53l0x_SEQUENCESTEP_MSRC)
new_msrc_timeout_mclks =
vl53l0x_timeoutMicrosecondsToMclks(timeouts.msrc_dss_tcc_us, period_pclks);
vl53l0x_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:
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x10);
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08);
vl53l0x_writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x02);
vl53l0x_writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x0C);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(ALGO_PHASECAL_LIM, 0x30);
vl53l0x_writeReg(0xFF, 0x00);
break;
case 10:
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x28);
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08);
vl53l0x_writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03);
vl53l0x_writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x09);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(ALGO_PHASECAL_LIM, 0x20);
vl53l0x_writeReg(0xFF, 0x00);
break;
case 12:
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x38);
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08);
vl53l0x_writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03);
vl53l0x_writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x08);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(ALGO_PHASECAL_LIM, 0x20);
vl53l0x_writeReg(0xFF, 0x00);
break;
case 14:
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_HIGH, 0x48);
vl53l0x_writeReg(FINAL_RANGE_CONFIG_VALID_PHASE_LOW, 0x08);
vl53l0x_writeReg(GLOBAL_CONFIG_VCSEL_WIDTH, 0x03);
vl53l0x_writeReg(ALGO_PHASECAL_CONFIG_TIMEOUT, 0x07);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(ALGO_PHASECAL_LIM, 0x20);
vl53l0x_writeReg(0xFF, 0x00);
break;
default:
// invalid period
return FALSE;
}
// apply new VCSEL period
vl53l0x_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 =
vl53l0x_timeoutMicrosecondsToMclks(timeouts.final_range_us, period_pclks);
if (enables.pre_range)
{
new_final_range_timeout_mclks += timeouts.pre_range_mclks;
}
vl53l0x_writeReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI,
vl53l0x_encodeTimeout(new_final_range_timeout_mclks));
// set_sequence_step_timeout end
}
else
{
// invalid type
return FALSE;
}
// "Finally, the timing budget must be re-applied"
vl53l0x_setMeasurementTimingBudget(measurement_timing_budget_us);
// "Perform the phase calibration. This is needed after changing on vcsel period."
// vl53l0x_perform_phase_calibration() begin
sequence_config = vl53l0x_readReg(SYSTEM_SEQUENCE_CONFIG);
vl53l0x_writeReg(SYSTEM_SEQUENCE_CONFIG, 0x02);
vl53l0x_performSingleRefCalibration(0x0);
vl53l0x_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(enum vcselPeriodType type)
{
if (type == VcselPeriodPreRange)
{
return decodeVcselPeriod(vl53l0x_readReg(PRE_RANGE_CONFIG_VCSEL_PERIOD));
}
else if (type == VcselPeriodFinalRange)
{
return decodeVcselPeriod(vl53l0x_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)
{
uint16_t osc_calibrate_val;
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
vl53l0x_writeReg(0x91, stop_variable);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x00);
if (period_ms != 0)
{
// continuous timed mode
// vl53l0x_SetInterMeasurementPeriodMilliSeconds() begin
osc_calibrate_val = vl53l0x_readReg16Bit(OSC_CALIBRATE_VAL);
if (osc_calibrate_val != 0)
{
period_ms *= osc_calibrate_val;
}
vl53l0x_writeReg32Bit(SYSTEM_INTERMEASUREMENT_PERIOD, period_ms);
// vl53l0x_SetInterMeasurementPeriodMilliSeconds() end
vl53l0x_writeReg(SYSRANGE_START, 0x04); // vl53l0x_REG_SYSRANGE_MODE_TIMED
}
else
{
// continuous back-to-back mode
vl53l0x_writeReg(SYSRANGE_START, 0x02); // vl53l0x_REG_SYSRANGE_MODE_BACKTOBACK
}
}
// Stop continuous measurements
// based on vl53l0x_StopMeasurement()
void vl53l0x_stopContinuous(void)
{
vl53l0x_writeReg(SYSRANGE_START, 0x01); // vl53l0x_REG_SYSRANGE_MODE_SINGLESHOT
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
vl53l0x_writeReg(0x91, 0x00);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_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)
{
uint16_t range ;
startTimeout();
while ((vl53l0x_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
range = vl53l0x_readReg16Bit(RESULT_RANGE_STATUS + 10);
vl53l0x_writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01);
if (vl53l0x_timeoutOccurred()) {
range = 0x1FFE;
}
return range;
}
// Performs a single-shot range measurement and returns the reading in
// millimeters
// based on vl53l0x_PerformSingleRangingMeasurement()
uint16_t vl53l0x_readRangeSingleMillimeters(void)
{
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
vl53l0x_writeReg(0x91, stop_variable);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x00);
vl53l0x_writeReg(SYSRANGE_START, 0x01);
// "Wait until start bit has been cleared"
startTimeout();
while (vl53l0x_readReg(SYSRANGE_START) & 0x01)
{
if (checkTimeoutExpired())
{
did_timeout = TRUE;
return 65535;
}
}
return vl53l0x_readRangeContinuousMillimeters();
}
// Did a timeout occur in one of the read functions since the last call to
// timeoutOccurred()?
uint8_t vl53l0x_timeoutOccurred()
{
uint8_t 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
uint8_t vl53l0x_getSpadInfo(uint8_t * count, uint8_t * type_is_aperture)
{
uint8_t tmp;
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x00);
vl53l0x_writeReg(0xFF, 0x06);
vl53l0x_writeReg(0x83, vl53l0x_readReg(0x83) | 0x04);
vl53l0x_writeReg(0xFF, 0x07);
vl53l0x_writeReg(0x81, 0x01);
vl53l0x_writeReg(0x80, 0x01);
vl53l0x_writeReg(0x94, 0x6b);
vl53l0x_writeReg(0x83, 0x00);
startTimeout();
while (vl53l0x_readReg(0x83) == 0x00)
{
if (checkTimeoutExpired()) { return FALSE; }
}
vl53l0x_writeReg(0x83, 0x01);
tmp = vl53l0x_readReg(0x92);
*count = tmp & 0x7f;
*type_is_aperture = (tmp >> 7) & 0x01;
vl53l0x_writeReg(0x81, 0x00);
vl53l0x_writeReg(0xFF, 0x06);
vl53l0x_writeReg(0x83, vl53l0x_readReg( 0x83 & ~0x04));
vl53l0x_writeReg(0xFF, 0x01);
vl53l0x_writeReg(0x00, 0x01);
vl53l0x_writeReg(0xFF, 0x00);
vl53l0x_writeReg(0x80, 0x00);
return TRUE;
}
// Get sequence step enables
// based on vl53l0x_GetSequenceStepEnables()
void vl53l0x_getSequenceStepEnables(struct SequenceStepEnables * enables)
{
uint8_t sequence_config = vl53l0x_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(struct SequenceStepEnables const * enables, struct SequenceStepTimeouts * timeouts)
{
timeouts->pre_range_vcsel_period_pclks = vl53l0x_getVcselPulsePeriod(VcselPeriodPreRange);
timeouts->msrc_dss_tcc_mclks = vl53l0x_readReg(MSRC_CONFIG_TIMEOUT_MACROP) + 1;
timeouts->msrc_dss_tcc_us =
vl53l0x_timeoutMclksToMicroseconds(timeouts->msrc_dss_tcc_mclks,
timeouts->pre_range_vcsel_period_pclks);
timeouts->pre_range_mclks =
vl53l0x_decodeTimeout(vl53l0x_readReg16Bit(PRE_RANGE_CONFIG_TIMEOUT_MACROP_HI));
timeouts->pre_range_us =
vl53l0x_timeoutMclksToMicroseconds(timeouts->pre_range_mclks,
timeouts->pre_range_vcsel_period_pclks);
timeouts->final_range_vcsel_period_pclks = vl53l0x_getVcselPulsePeriod(VcselPeriodFinalRange);
timeouts->final_range_mclks =
vl53l0x_decodeTimeout(vl53l0x_readReg16Bit(FINAL_RANGE_CONFIG_TIMEOUT_MACROP_HI));
if (enables->pre_range)
{
timeouts->final_range_mclks -= timeouts->pre_range_mclks;
}
timeouts->final_range_us =
vl53l0x_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()
uint8_t vl53l0x_performSingleRefCalibration(uint8_t vhv_init_byte)
{
vl53l0x_writeReg(SYSRANGE_START, 0x01 | vhv_init_byte); // vl53l0x_REG_SYSRANGE_MODE_START_STOP
startTimeout();
while ((vl53l0x_readReg(RESULT_INTERRUPT_STATUS) & 0x07) == 0)
{
if (checkTimeoutExpired()) { return FALSE; }
}
vl53l0x_writeReg(SYSTEM_INTERRUPT_CLEAR, 0x01);
vl53l0x_writeReg(SYSRANGE_START, 0x00);
return TRUE;
}
使用感について
目には見えない赤外線940nmのレーザー光が対象物から反射してくるまでの時間を計測する事で距離を割り出す方式なので対象物が明るすぎたり真っ黒だったりすると反射光を検出できず測定できない事がありました、また鏡面や透明ガラスなども全反射して入射光が反ってこない角度では検出する事ができませんでした。 室内であれば確かに２m近くまで検出できましたが、日中の明るい野外では概ね60cm程度までしか検出できないので用途を選ぶようです。
反応速度は結構早いので手を振るジェスチャー検出とか、直前を物体が横切ったのを検出するとかの用途にも使えそうです、室内で使うロボットの衝突回避センサーとかにはピッタリかと思いますが、野外で使うドローンの衝突防止の目的には使えなさそうです。
このTOFセンサを複数使用する場合は、同じI2Cバスに接続しSHDNピンを個別に制御することで異なるI2Cアドレスに設定する事ができ、測距完了時にGPIO1ピンで割り込みを掛けることで順次最短の間隔周期で計測する事が可能になります。
複数使用のサンプルコード
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