DipTrace | Paynter's Palace

Posted 13 March 2021

Back in May of last year I started the process of replacing the ultrasonic distance sensors on Wall-E2, my autonomous wall-following robot, with two side-looking arrays of STMicroelectronics’ VL53L0X infrared laser ‘Time-of-Flight’ distance sensor. Later that same year I upgraded the installation by adding a rear distance sensor as well, as shown in the following photo:

left-hand VL53L0X array and rear sensor shown. Identical 3-elelment array on the other side

All went swimmingly until I started having problems when Wall-E2 connected up to its charger. Wall-E2 connecting to its charger is a pretty dynamic event, as it has to build up enough speed to make sure the charging probe seats into the charging jack properly. I discovered that about every other time Wall-E2 connected, the distance sensors would start reporting ‘-1’ instead of the actual distances. This meant that when Wall-E2 disconnected from charging, it had no idea what to do or which way to turn. This didn’t happen all the time, but often enough to be very worrisome.

After some head-scratching and program instrumentation I became convinced this was a real issue, and I posted on the ST Micro’s forum about the issue. ST Micro’s VL53L0X expert John E. Kvam answered with this post:

The VL53L0X sensor will not return a -1. The user manual does define a -1 error, but it states that this cannot happen. What does return a -1 is an I2C timeout.
And I think that is what is killing you. The I2C is notorious for being basically unreliable. And the major symptom of a dropped bit (the most likely failure), is that the bus is stuck low. (When nothing is being transmitted both the clock and data lines should be high.) Philips designed the I2C bus and NXP bought Philips. So the NXP site has some documentation on how to tweak the bus. I’d read and understand that.
One other possibility is that one or more of the sensors rebooted – perhaps due to power glitch. If this happens the sensor will revert to it’s base I2C address.
If you’ve changed all your addresses there should be nothing at address 0x29 (0x52/0x53). You could occasionally ping the base address – and if you ever got an answer, you would would know you had a reboot of some kind.

After thinking about this some more, I realized that there is a good chance that the I2C ‘daisy-chain’ wiring and/or the power/ground connections are getting interrupted due to the impulse generated when Wall-E2 hits the charging station stop, and this is causing one or more of the sensors to drop out. I thought I had done a very careful job with the I2C/power ‘daisy-chain’, but I had thought that about a previous effort where I found a faulty ground connection, so I knew it was a possibility.

After thinking about this some more, it occurred to me that I could eliminate most of the point-point wiring issues by creating a PCB to house the VL53L0X modules, with a single 4-pin connector for I2C and power. I had made a PCB some years before using DipTrace that had turned out petty well, so making one for the very simple VL53L0X wiring scheme should be a piece of cake.

Well, as it turned out, designing the PCB was the easy part. However, when it came to the part about having the boards actually manufactured, I was in for a bit of a shock. For my previous board I used DipTrace’s ‘baked-in’ manufacturer Bay Area Circuits to purchase 5 boards for around $30, but when I tried this same trick with my new board, the minimum charge for boards from BAC was $150 – ouch!

After a lot of web searching and research, I eventually found the Chinese company JLCPCB and discovered they have a very nice document that shows how to export the required files from DipTrace and upload them to their site. Took me about 30 minutes to go through the process the first time, and now I have my 5ea boards ordered for a grand total of about $15USD. Only a 10:1 ratio from BAC to JLCPCB. I can’t imagine how BAC can stay in business, and I can’t imagine why DipTrace has that company ‘baked in’ and not JLCPCB. DipTrace must be getting a heck of a kickback from BAC!

Less than 10 days later, I had the finished PCBs in my hand – wow! Here’s a photo showing two PCB’s installed on Wall-E2. I installed 4-pin headers on both ends of the near PCB in order to daisy-chain the I2C and power connections to the rear distance sensor (hidden behind the red ‘rear bumper’ block in the right background).

New VL53L0X array PCB to replace all the hand-wired I2C/Power connections.

Comparing the ‘before’ and ‘after’ photos, it is easy to see that the PCB installation eliminates two 4-pin connectors and a three-loop daisy chain on one side of the robot, and two 4-pin connectors and a four-loop daisy chain on the other side (the one that also connects to the rear distance sensor. Moreover, now none of the 3 connectors used for all seven sensors has more than one wire per pin.

Hopefully this upgrade will eliminate (or at least significantly suppress) wiring and/or connector issues associated with the charger-connect ‘impulse’ – we’ll see

25 March 2021 Update:

After getting the new PCBs installed and some other connection issues solved, Wall-E2’s sensors seem to be a lot more reliable. However, I decided to take this opportunity to study John Kvam’s idea of re-initializing all seven sensors if one of them happens to show up at the default VL53L0X I2C address.

So, I modified the Teensy 3.5 VL53L0X array management code to abstract the sensor init code from setup() to its own function so it can be called if the program detects a sensor at the default I2C address, and then added code in loop() to do just that. Here’s the detection code:

  //03/25/21 see if any VL53L0X responds to a query at the default address
  Wire1.beginTransmission(DEFAULT_VL53L0X_ADDR);
  if (!Wire1.endTransmission() != 0)
  {
    Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire1!\n", DEFAULT_VL53L0X_ADDR);
    InitAllSensors();
  }
  Wire2.beginTransmission(DEFAULT_VL53L0X_ADDR);
  if (!Wire2.endTransmission() != 0)
  {
    Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire2!\n", DEFAULT_VL53L0X_ADDR);
    InitAllSensors();
  }

//03/25/21 see if any VL53L0X responds to a query at the default address

Wire1.beginTransmission(DEFAULT_VL53L0X_ADDR);

if (!Wire1.endTransmission() != 0)

{

Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire1!\n", DEFAULT_VL53L0X_ADDR);

InitAllSensors();

}

Wire2.beginTransmission(DEFAULT_VL53L0X_ADDR);

if (!Wire2.endTransmission() != 0)

{

Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire2!\n", DEFAULT_VL53L0X_ADDR);

InitAllSensors();

}

and here’s the new ‘InitAllSensors()’ routine:

bool InitAllSensors()
{
  //Purpose: Initialize all seven VL53L0X sensors
  //Provenance: 03/22/21

  Serial.printf("Initializing VL53L0X Sensor Array Elements\n");
 
  //Put all sensors in reset mode by pulling XSHUT low
  digitalWrite(RF_XSHUT_PIN, LOW);
  digitalWrite(RC_XSHUT_PIN, LOW);
  digitalWrite(RR_XSHUT_PIN, LOW);

  digitalWrite(LF_XSHUT_PIN, LOW);
  digitalWrite(LC_XSHUT_PIN, LOW);
  digitalWrite(LR_XSHUT_PIN, LOW);

  //added 10/23/20 for rear sensor
  pinMode(Rear_XSHUT_PIN, OUTPUT);
  digitalWrite(Rear_XSHUT_PIN, LOW);


  //now bring lidar_RF only out of reset and set it's address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RF_XSHUT_PIN, INPUT);
  delay(10);

  bool retval = true;

  if (!lidar_RF.init())
  {
    Serial.println("Failed to detect and initialize lidar_RF!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RF.setMeasurementTimingBudget(20000);
  lidar_RF.startContinuous();


  lidar_RF.setAddress(DEFAULT_VL53L0X_ADDR + 1);
  Serial.printf("lidar_RF address is 0x%x\n", lidar_RF.getAddress());

  delay(100);

  //now bring lidar_RC only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RC_XSHUT_PIN, INPUT);

  delay(10);
  if (!lidar_RC.init())
  {
    Serial.println("Failed to detect and initialize lidar_RC!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RC.setMeasurementTimingBudget(20000);
  lidar_RC.startContinuous();

  lidar_RC.setAddress(DEFAULT_VL53L0X_ADDR + 2);
  Serial.printf("lidar_RC address is 0x%x\n", lidar_RC.getAddress());

  delay(100);

  //now bring lidar_RR only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RR_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_RR.init())
  {
    Serial.println("Failed to detect and initialize lidar_RR!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RR.setMeasurementTimingBudget(20000);
  lidar_RR.startContinuous();

  lidar_RR.setAddress(DEFAULT_VL53L0X_ADDR + 3);
  Serial.printf("lidar_RR address is 0x%x\n", lidar_RR.getAddress());

  delay(100);

  //now bring lidar_LF only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LF_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_LF.init())
  {
    Serial.println("Failed to detect and initialize lidar_LF!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LF.setMeasurementTimingBudget(20000);
  lidar_LF.startContinuous();

  lidar_LF.setAddress(DEFAULT_VL53L0X_ADDR + 4);
  Serial.printf("lidar_LF address is 0x%x\n", lidar_LF.getAddress());

  delay(100);

  //now bring lidar_LC only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LC_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_LC.init())
  {
    Serial.println("Failed to detect and initialize lidar_LC!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LC.setMeasurementTimingBudget(20000);
  lidar_LC.startContinuous();

  lidar_LC.setAddress(DEFAULT_VL53L0X_ADDR + 5);
  Serial.printf("lidar_LC address is 0x%x\n", lidar_LC.getAddress());

  delay(100);

  //now bring lidar_LR only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LR_XSHUT_PIN, INPUT);

  if (!lidar_LR.init())
  {
    Serial.println("Failed to detect and initialize lidar_LR!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LR.setMeasurementTimingBudget(20000);
  lidar_LR.startContinuous();

  lidar_LR.setAddress(DEFAULT_VL53L0X_ADDR + 6);
  Serial.printf("lidar_LR address is 0x%x\n", lidar_LR.getAddress());

  delay(100);

  //added 10/23/20 for rear sensor
  //now bring lidar_Rear only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(Rear_XSHUT_PIN, INPUT);

  if (!lidar_Rear.init())
  {
    Serial.println("Failed to detect and initialize lidar_Rear!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_Rear.setMeasurementTimingBudget(20000);
  lidar_Rear.startContinuous();

  lidar_Rear.setAddress(DEFAULT_VL53L0X_ADDR + 7);
  Serial.printf("lidar_Rear address is 0x%x\n", lidar_Rear.getAddress());

  return retval;
}

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bool InitAllSensors()

{

//Purpose: Initialize all seven VL53L0X sensors

//Provenance: 03/22/21

Serial.printf("Initializing VL53L0X Sensor Array Elements\n");

//Put all sensors in reset mode by pulling XSHUT low

digitalWrite(RF_XSHUT_PIN, LOW);

digitalWrite(RC_XSHUT_PIN, LOW);

digitalWrite(RR_XSHUT_PIN, LOW);

digitalWrite(LF_XSHUT_PIN, LOW);

digitalWrite(LC_XSHUT_PIN, LOW);

digitalWrite(LR_XSHUT_PIN, LOW);

//added 10/23/20 for rear sensor

pinMode(Rear_XSHUT_PIN, OUTPUT);

digitalWrite(Rear_XSHUT_PIN, LOW);

//now bring lidar_RF only out of reset and set it's address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RF_XSHUT_PIN, INPUT);

delay(10);

bool retval = true;

if (!lidar_RF.init())

{

Serial.println("Failed to detect and initialize lidar_RF!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RF.setMeasurementTimingBudget(20000);

lidar_RF.startContinuous();

lidar_RF.setAddress(DEFAULT_VL53L0X_ADDR + 1);

Serial.printf("lidar_RF address is 0x%x\n", lidar_RF.getAddress());

delay(100);

//now bring lidar_RC only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RC_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_RC.init())

{

Serial.println("Failed to detect and initialize lidar_RC!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RC.setMeasurementTimingBudget(20000);

lidar_RC.startContinuous();

lidar_RC.setAddress(DEFAULT_VL53L0X_ADDR + 2);

Serial.printf("lidar_RC address is 0x%x\n", lidar_RC.getAddress());

delay(100);

//now bring lidar_RR only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RR_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_RR.init())

{

Serial.println("Failed to detect and initialize lidar_RR!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RR.setMeasurementTimingBudget(20000);

lidar_RR.startContinuous();

lidar_RR.setAddress(DEFAULT_VL53L0X_ADDR + 3);

Serial.printf("lidar_RR address is 0x%x\n", lidar_RR.getAddress());

delay(100);

//now bring lidar_LF only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LF_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_LF.init())

{

Serial.println("Failed to detect and initialize lidar_LF!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LF.setMeasurementTimingBudget(20000);

lidar_LF.startContinuous();

lidar_LF.setAddress(DEFAULT_VL53L0X_ADDR + 4);

Serial.printf("lidar_LF address is 0x%x\n", lidar_LF.getAddress());

delay(100);

//now bring lidar_LC only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LC_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_LC.init())

{

Serial.println("Failed to detect and initialize lidar_LC!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LC.setMeasurementTimingBudget(20000);

lidar_LC.startContinuous();

lidar_LC.setAddress(DEFAULT_VL53L0X_ADDR + 5);

Serial.printf("lidar_LC address is 0x%x\n", lidar_LC.getAddress());

delay(100);

//now bring lidar_LR only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LR_XSHUT_PIN, INPUT);

if (!lidar_LR.init())

{

Serial.println("Failed to detect and initialize lidar_LR!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LR.setMeasurementTimingBudget(20000);

lidar_LR.startContinuous();

lidar_LR.setAddress(DEFAULT_VL53L0X_ADDR + 6);

Serial.printf("lidar_LR address is 0x%x\n", lidar_LR.getAddress());

delay(100);

//added 10/23/20 for rear sensor

//now bring lidar_Rear only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(Rear_XSHUT_PIN, INPUT);

if (!lidar_Rear.init())

{

Serial.println("Failed to detect and initialize lidar_Rear!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_Rear.setMeasurementTimingBudget(20000);

lidar_Rear.startContinuous();

lidar_Rear.setAddress(DEFAULT_VL53L0X_ADDR + 7);

Serial.printf("lidar_Rear address is 0x%x\n", lidar_Rear.getAddress());

return retval;

}

And here is the complete Teensy program for managing the VL53L0X arrays:

/*
    Name:       Teensy_7VL53L0X_I2C_Slave_V3.ino
    Created:	1/24/2021 4:03:35 PM
    Author:     FRANKNEWXPS15\Frank

    This is the 'final' version of the Teensy 3.5 project to manage all 
    seven VL53L0X lidar distance sensors, three on left, three on right, 
    and now including a rear distance sensor.  As of this date it was an
    identical copy of the TeensyHexVL53L0XHighSpeedDemo project, just
    renamed for clarity.  This program was uploaded to the Teensy on 
    Wall-E2's second deck on 1/24/21

    Notes:
      02/01/21 Added code in requestEvent() to blink LED_BUILTIN when distance data is requested
      03/22/21 Abstracted sensor init code from setup() to InitAllSensors() so can use elsewhere

*/

#include <Wire.h> //using Wire.h here instead of i2c_t3.h for multiple I2C bus access
#include <VL53L0X.h>
#include "I2C_Anything.h" //local version modified to use Wire.h vs SBWire

volatile uint8_t request_type;

const int SETUP_DURATION_OUTPUT_PIN = 33;
const int REQUEST_EVENT_DURATION_OUTPUT_PIN = 34;
bool bTeensyReady = false;


enum VL53L0X_REQUEST
{
  VL53L0X_READYCHECK, //added 11/10/20 to prevent bad reads during Teensy setup()
  VL53L0X_CENTERS_ONLY,
  VL53L0X_RIGHT,
  VL53L0X_LEFT,
  VL53L0X_ALL, //added 08/05/20, chg 'BOTH' to 'ALL' 10/31/20
  VL53L0X_REAR_ONLY //added 10/24/20
};


//right side array
VL53L0X lidar_RF(&Wire1);
VL53L0X lidar_RC(&Wire1);
VL53L0X lidar_RR(&Wire1);

//left side array
VL53L0X lidar_LF(&Wire2);
VL53L0X lidar_LC(&Wire2);
VL53L0X lidar_LR(&Wire2);

//XSHUT required for I2C address init 
//right side array
const int RF_XSHUT_PIN = 23;
const int RC_XSHUT_PIN = 22;
const int RR_XSHUT_PIN = 21;

//left side array
const int LF_XSHUT_PIN = 5;
const int LC_XSHUT_PIN = 6;
const int LR_XSHUT_PIN = 7;

const int MAX_LIDAR_RANGE_MM = 1000; //make it obvious when nearest object is out of range

//right side array
uint16_t RF_Dist_mm;
uint16_t RC_Dist_mm;
uint16_t RR_Dist_mm;

//left side array
uint16_t LF_Dist_mm;
uint16_t LC_Dist_mm;
uint16_t LR_Dist_mm;


float RightSteeringVal;
float LeftSteeringVal;

const int SLAVE_ADDRESS = 0x20; //just a guess for now
const int DEFAULT_VL53L0X_ADDR = 0x29;

//10/23/20 added rear distance sensor
VL53L0X lidar_Rear(&Wire2); //added to Wire2 daisy-chain
const int Rear_XSHUT_PIN = 8;
uint16_t Rear_Dist_mm;

void setup()
{
  // wait until serial port opens ... For 5 seconds max
  Serial.begin(115200);
  delay(5000);

  pinMode(LED_BUILTIN, OUTPUT);
  bTeensyReady = false; //11/10/20 added to prevent bad data reads by main controller

  pinMode(SETUP_DURATION_OUTPUT_PIN, OUTPUT);
  pinMode(REQUEST_EVENT_DURATION_OUTPUT_PIN, OUTPUT);
  digitalWrite(SETUP_DURATION_OUTPUT_PIN, HIGH);

  Wire.begin(SLAVE_ADDRESS); //set Teensy Wire0 port up as slave
  Wire.onRequest(requestEvent);  //ISR for I2C requests from master (Mega 2560)
  Wire.onReceive(receiveEvent); //ISR for I2C data from master (Mega 2560)

  Wire1.begin();
  Wire2.begin();


  pinMode(RF_XSHUT_PIN, OUTPUT);
  pinMode(RC_XSHUT_PIN, OUTPUT);
  pinMode(RR_XSHUT_PIN, OUTPUT);

  pinMode(LF_XSHUT_PIN, OUTPUT);
  pinMode(LC_XSHUT_PIN, OUTPUT);
  pinMode(LR_XSHUT_PIN, OUTPUT);

  //03/22/21 sensor init abstracted to function so can call from loop()
  bool bSensorsOK = InitAllSensors();
  Serial.printf("Just after InitAllSensors()\n");

  if (!bSensorsOK)
  {
    Serial.printf("Sensor initialization failed - quitting!\n");
    while (true)
    {

    }
  }

  Serial.printf("Msec\tLFront\tLCtr\tLRear\tRFront\tRCtr\tRRear\tLSteer\tRSteer\tRear\n");

  //02/01/21 now using LED_BUILTIN to provide visible indication of I2C data requests
  pinMode(LED_BUILTIN, OUTPUT);

  digitalWrite(SETUP_DURATION_OUTPUT_PIN, LOW);
  bTeensyReady = true; //11/10/20 added to prevent bad data reads by main controller
}

void loop()
{
  //from Pololu forum post
  RF_Dist_mm = lidar_RF.readRangeContinuousMillimeters();
  RC_Dist_mm = lidar_RC.readRangeContinuousMillimeters();
  RR_Dist_mm = lidar_RR.readRangeContinuousMillimeters();

  RightSteeringVal = (RF_Dist_mm - RR_Dist_mm) / 100.f; //rev 06/21/20 see PPalace post

  //from Pololu forum post
  LF_Dist_mm = lidar_LF.readRangeContinuousMillimeters();
  LC_Dist_mm = lidar_LC.readRangeContinuousMillimeters();
  LR_Dist_mm = lidar_LR.readRangeContinuousMillimeters();

  LeftSteeringVal = (LF_Dist_mm - LR_Dist_mm) / 100.f; //rev 06/21/20 see PPalace post

  //added 10/23/20 for rear sensor
  Rear_Dist_mm = lidar_Rear.readRangeContinuousMillimeters();


  Serial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",
    millis(), RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, Rear_Dist_mm);

  delay(100);

  //03/25/21 see if any VL53L0X responds to a query at the default address
  Wire1.beginTransmission(DEFAULT_VL53L0X_ADDR);
  if (!Wire1.endTransmission() != 0)
  {
    Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire1!\n", DEFAULT_VL53L0X_ADDR);
    InitAllSensors();
  }
  Wire2.beginTransmission(DEFAULT_VL53L0X_ADDR);
  if (!Wire2.endTransmission() != 0)
  {
    Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire2!\n", DEFAULT_VL53L0X_ADDR);
    InitAllSensors();
  }

}

// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent()
{
  //Purpose: Send requested sensor data to the Mega controller via main I2C bus
  //Inputs: 
  //  request_type = uint8_t value denoting type of data requested (from receiveEvent())
  //      0 = left & right center distances only
  //      1 = right side front, center and rear distances, plus steering value
  //      2 = left side front, center and rear distances, plus steering value
  //      3 = both side front, center and rear distances, plus both steering values
//Outputs:
  //  Requested data sent to master
  //Notes:
  //  08/05/20 added VL53L0X_ALL request type to get both sides at once
  //  10/24/20 added VL53L0X_REAR_ONLY request type
  //  11/09/20 added write to pin for O'scope monitoring
  //  02/01/21 aded LED_PIN blink


//DEBUG!!
    //Serial.printf("RequestEvent() with request_type = %d: VL53L0X Front/Center/Rear distances = %d, %d, %d\n", 
    //    request_type, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm);
//DEBUG!!

  digitalWrite(REQUEST_EVENT_DURATION_OUTPUT_PIN, HIGH);
  digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));

  switch (request_type)
  {
  case 	VL53L0X_READYCHECK: //added 11/10/20 to prevent bad reads during Teensy setup()
    Serial.printf("in VL53L0X_READYCHECK case at %lu with bTeensyReady = %d\n", millis(), bTeensyReady);
    I2C_writeAnything(bTeensyReady);
    break;

  case VL53L0X_CENTERS_ONLY:

    //DEBUG!!
            //data_size = 2*sizeof(uint16_t);
            //Serial.printf("Sending %d bytes LC_Dist_mm = %d, RC_Dist_mm = %d to master\n", data_size, LC_Dist_mm, RC_Dist_mm);
    //DEBUG!!

    I2C_writeAnything(RC_Dist_mm);
    I2C_writeAnything(LC_Dist_mm);
    break;

  case VL53L0X_RIGHT:

    //DEBUG!!
            //data_size = 3 * sizeof(uint16_t) + sizeof(float);
            //Serial.printf("Sending %d bytes RF/RC/RR/RS vals = %d, %d, %d, %3.2f to master\n",
            //    data_size, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, RightSteeringVal);
    //DEBUG!!

    I2C_writeAnything(RF_Dist_mm);
    I2C_writeAnything(RC_Dist_mm);
    I2C_writeAnything(RR_Dist_mm);
    I2C_writeAnything(RightSteeringVal);
    break;

  case VL53L0X_LEFT:

    //DEBUG!!
            //data_size = 3 * sizeof(uint16_t) + sizeof(float);
            //Serial.printf("Sending %d bytes LF/LC/LR/LS vals = %d, %d, %d, %3.2f to master\n",
            //    data_size, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, LeftSteeringVal);
    //DEBUG!!

    I2C_writeAnything(LF_Dist_mm);
    I2C_writeAnything(LC_Dist_mm);
    I2C_writeAnything(LR_Dist_mm);
    I2C_writeAnything(LeftSteeringVal);
    break;

  case VL53L0X_ALL:
    //added 08/05/20 to get data from both sides at once
    //10/31/20 chg to VL53L0X_ALL & report all 7 sensor values

//DEBUG!!
    //data_size = 3 * sizeof(uint16_t) + sizeof(float);
    //Serial.printf("Sending %d bytes LF/LC/LR/LS vals = %d, %d, %d, %3.2f to master\n",
    //    data_size, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, LeftSteeringVal);
    //Serial.printf("left %d\t%d\t%d\t%d\t%2.3f",
    //  LF_Dist_mm, LC_Dist_mm, LR_Dist_mm);
//DEBUG!!

    //Serial.printf("In VL53L0X_ALL case\n");

    //left side  
    I2C_writeAnything(LF_Dist_mm);
    I2C_writeAnything(LC_Dist_mm);
    I2C_writeAnything(LR_Dist_mm);
    I2C_writeAnything(LeftSteeringVal);


    //DEBUG!!
        //data_size = 3 * sizeof(uint16_t) + sizeof(float);
        //Serial.printf("Sending %d bytes RF/RC/RR/RS vals = %d, %d, %d, %3.2f to master\n",
        //    data_size, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, LeftSteeringVal);

        //Serial.printf(" right %d\t%d\t%d\t%d\t%2.3f\n",
        //RF_Dist_mm, RC_Dist_mm, RR_Dist_mm);
    //DEBUG!!

       //right side
    I2C_writeAnything(RF_Dist_mm);
    I2C_writeAnything(RC_Dist_mm);
    I2C_writeAnything(RR_Dist_mm);
    I2C_writeAnything(RightSteeringVal);

    //10/31/20 now also reporting rear sensor value
    I2C_writeAnything(Rear_Dist_mm);

    break;

  case VL53L0X_REAR_ONLY:

    //DEBUG!!
      //data_size = sizeof(uint16_t);
      //Serial.printf("Sending %d bytes Rear_Dist_mm = %d to master\n", data_size, Rear_Dist_mm);
    //DEBUG!!

    I2C_writeAnything(Rear_Dist_mm);
    break;

  default:
    break;
  }

  digitalWrite(REQUEST_EVENT_DURATION_OUTPUT_PIN, LOW);
}

//
// handle Rx Event (incoming I2C data)
//
void receiveEvent(int numBytes)
{
  //Purpose: capture data request type from Mega I2C master
  //Inputs:
  //  numBytes = int value denoting number of bytes received from master
  //Outputs:
  //  uint8_t request_type filled with request type value from master


//DEBUG!!
    //Serial.printf("receiveEvent(%d)\n", numBytes);
//DEBUG!!

  I2C_readAnything(request_type);

  //DEBUG!!
      //Serial.printf("receiveEvent: Got %d from master\n", request_type);
  //DEBUG!!
}
bool InitAllSensors()
{
  //Purpose: Initialize all seven VL53L0X sensors
  //Provenance: 03/22/21

  Serial.printf("Initializing VL53L0X Sensor Array Elements\n");
 
  //Put all sensors in reset mode by pulling XSHUT low
  digitalWrite(RF_XSHUT_PIN, LOW);
  digitalWrite(RC_XSHUT_PIN, LOW);
  digitalWrite(RR_XSHUT_PIN, LOW);

  digitalWrite(LF_XSHUT_PIN, LOW);
  digitalWrite(LC_XSHUT_PIN, LOW);
  digitalWrite(LR_XSHUT_PIN, LOW);

  //added 10/23/20 for rear sensor
  pinMode(Rear_XSHUT_PIN, OUTPUT);
  digitalWrite(Rear_XSHUT_PIN, LOW);


  //now bring lidar_RF only out of reset and set it's address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RF_XSHUT_PIN, INPUT);
  delay(10);

  bool retval = true;

  if (!lidar_RF.init())
  {
    Serial.println("Failed to detect and initialize lidar_RF!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RF.setMeasurementTimingBudget(20000);
  lidar_RF.startContinuous();


  lidar_RF.setAddress(DEFAULT_VL53L0X_ADDR + 1);
  Serial.printf("lidar_RF address is 0x%x\n", lidar_RF.getAddress());

  delay(100);

  //now bring lidar_RC only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RC_XSHUT_PIN, INPUT);

  delay(10);
  if (!lidar_RC.init())
  {
    Serial.println("Failed to detect and initialize lidar_RC!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RC.setMeasurementTimingBudget(20000);
  lidar_RC.startContinuous();

  lidar_RC.setAddress(DEFAULT_VL53L0X_ADDR + 2);
  Serial.printf("lidar_RC address is 0x%x\n", lidar_RC.getAddress());

  delay(100);

  //now bring lidar_RR only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(RR_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_RR.init())
  {
    Serial.println("Failed to detect and initialize lidar_RR!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_RR.setMeasurementTimingBudget(20000);
  lidar_RR.startContinuous();

  lidar_RR.setAddress(DEFAULT_VL53L0X_ADDR + 3);
  Serial.printf("lidar_RR address is 0x%x\n", lidar_RR.getAddress());

  delay(100);

  //now bring lidar_LF only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LF_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_LF.init())
  {
    Serial.println("Failed to detect and initialize lidar_LF!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LF.setMeasurementTimingBudget(20000);
  lidar_LF.startContinuous();

  lidar_LF.setAddress(DEFAULT_VL53L0X_ADDR + 4);
  Serial.printf("lidar_LF address is 0x%x\n", lidar_LF.getAddress());

  delay(100);

  //now bring lidar_LC only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LC_XSHUT_PIN, INPUT);
  delay(10);

  if (!lidar_LC.init())
  {
    Serial.println("Failed to detect and initialize lidar_LC!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LC.setMeasurementTimingBudget(20000);
  lidar_LC.startContinuous();

  lidar_LC.setAddress(DEFAULT_VL53L0X_ADDR + 5);
  Serial.printf("lidar_LC address is 0x%x\n", lidar_LC.getAddress());

  delay(100);

  //now bring lidar_LR only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(LR_XSHUT_PIN, INPUT);

  if (!lidar_LR.init())
  {
    Serial.println("Failed to detect and initialize lidar_LR!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_LR.setMeasurementTimingBudget(20000);
  lidar_LR.startContinuous();

  lidar_LR.setAddress(DEFAULT_VL53L0X_ADDR + 6);
  Serial.printf("lidar_LR address is 0x%x\n", lidar_LR.getAddress());

  delay(100);

  //added 10/23/20 for rear sensor
  //now bring lidar_Rear only out of reset, initialize it, and set its address
  //input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over
  pinMode(Rear_XSHUT_PIN, INPUT);

  if (!lidar_Rear.init())
  {
    Serial.println("Failed to detect and initialize lidar_Rear!");
    //while (1) {}
    retval = false;
  }

  //from Pololu forum post
  lidar_Rear.setMeasurementTimingBudget(20000);
  lidar_Rear.startContinuous();

  lidar_Rear.setAddress(DEFAULT_VL53L0X_ADDR + 7);
  Serial.printf("lidar_Rear address is 0x%x\n", lidar_Rear.getAddress());

  return retval;
}

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Name: Teensy_7VL53L0X_I2C_Slave_V3.ino

Created: 1/24/2021 4:03:35 PM

Author: FRANKNEWXPS15\Frank

This is the 'final' version of the Teensy 3.5 project to manage all

seven VL53L0X lidar distance sensors, three on left, three on right,

and now including a rear distance sensor. As of this date it was an

identical copy of the TeensyHexVL53L0XHighSpeedDemo project, just

renamed for clarity. This program was uploaded to the Teensy on

Wall-E2's second deck on 1/24/21

Notes:

02/01/21 Added code in requestEvent() to blink LED_BUILTIN when distance data is requested

03/22/21 Abstracted sensor init code from setup() to InitAllSensors() so can use elsewhere

#include <Wire.h> //using Wire.h here instead of i2c_t3.h for multiple I2C bus access

#include <VL53L0X.h>

#include "I2C_Anything.h" //local version modified to use Wire.h vs SBWire

volatile uint8_t request_type;

const int SETUP_DURATION_OUTPUT_PIN = 33;

const int REQUEST_EVENT_DURATION_OUTPUT_PIN = 34;

bool bTeensyReady = false;

enum VL53L0X_REQUEST

{

VL53L0X_READYCHECK, //added 11/10/20 to prevent bad reads during Teensy setup()

VL53L0X_CENTERS_ONLY,

VL53L0X_RIGHT,

VL53L0X_LEFT,

VL53L0X_ALL, //added 08/05/20, chg 'BOTH' to 'ALL' 10/31/20

VL53L0X_REAR_ONLY //added 10/24/20

};

//right side array

VL53L0X lidar_RF(&Wire1);

VL53L0X lidar_RC(&Wire1);

VL53L0X lidar_RR(&Wire1);

//left side array

VL53L0X lidar_LF(&Wire2);

VL53L0X lidar_LC(&Wire2);

VL53L0X lidar_LR(&Wire2);

//XSHUT required for I2C address init

//right side array

const int RF_XSHUT_PIN = 23;

const int RC_XSHUT_PIN = 22;

const int RR_XSHUT_PIN = 21;

//left side array

const int LF_XSHUT_PIN = 5;

const int LC_XSHUT_PIN = 6;

const int LR_XSHUT_PIN = 7;

const int MAX_LIDAR_RANGE_MM = 1000; //make it obvious when nearest object is out of range

//right side array

uint16_t RF_Dist_mm;

uint16_t RC_Dist_mm;

uint16_t RR_Dist_mm;

//left side array

uint16_t LF_Dist_mm;

uint16_t LC_Dist_mm;

uint16_t LR_Dist_mm;

float RightSteeringVal;

float LeftSteeringVal;

const int SLAVE_ADDRESS = 0x20; //just a guess for now

const int DEFAULT_VL53L0X_ADDR = 0x29;

//10/23/20 added rear distance sensor

VL53L0X lidar_Rear(&Wire2); //added to Wire2 daisy-chain

const int Rear_XSHUT_PIN = 8;

uint16_t Rear_Dist_mm;

void setup()

{

// wait until serial port opens ... For 5 seconds max

Serial.begin(115200);

delay(5000);

pinMode(LED_BUILTIN, OUTPUT);

bTeensyReady = false; //11/10/20 added to prevent bad data reads by main controller

pinMode(SETUP_DURATION_OUTPUT_PIN, OUTPUT);

pinMode(REQUEST_EVENT_DURATION_OUTPUT_PIN, OUTPUT);

digitalWrite(SETUP_DURATION_OUTPUT_PIN, HIGH);

Wire.begin(SLAVE_ADDRESS); //set Teensy Wire0 port up as slave

Wire.onRequest(requestEvent); //ISR for I2C requests from master (Mega 2560)

Wire.onReceive(receiveEvent); //ISR for I2C data from master (Mega 2560)

Wire1.begin();

Wire2.begin();

pinMode(RF_XSHUT_PIN, OUTPUT);

pinMode(RC_XSHUT_PIN, OUTPUT);

pinMode(RR_XSHUT_PIN, OUTPUT);

pinMode(LF_XSHUT_PIN, OUTPUT);

pinMode(LC_XSHUT_PIN, OUTPUT);

pinMode(LR_XSHUT_PIN, OUTPUT);

//03/22/21 sensor init abstracted to function so can call from loop()

bool bSensorsOK = InitAllSensors();

Serial.printf("Just after InitAllSensors()\n");

if (!bSensorsOK)

{

Serial.printf("Sensor initialization failed - quitting!\n");

while (true)

{

}

Serial.printf("Msec\tLFront\tLCtr\tLRear\tRFront\tRCtr\tRRear\tLSteer\tRSteer\tRear\n");

//02/01/21 now using LED_BUILTIN to provide visible indication of I2C data requests

pinMode(LED_BUILTIN, OUTPUT);

digitalWrite(SETUP_DURATION_OUTPUT_PIN, LOW);

bTeensyReady = true; //11/10/20 added to prevent bad data reads by main controller

}

void loop()

{

//from Pololu forum post

RF_Dist_mm = lidar_RF.readRangeContinuousMillimeters();

RC_Dist_mm = lidar_RC.readRangeContinuousMillimeters();

RR_Dist_mm = lidar_RR.readRangeContinuousMillimeters();

RightSteeringVal = (RF_Dist_mm - RR_Dist_mm) / 100.f; //rev 06/21/20 see PPalace post

//from Pololu forum post

LF_Dist_mm = lidar_LF.readRangeContinuousMillimeters();

LC_Dist_mm = lidar_LC.readRangeContinuousMillimeters();

LR_Dist_mm = lidar_LR.readRangeContinuousMillimeters();

LeftSteeringVal = (LF_Dist_mm - LR_Dist_mm) / 100.f; //rev 06/21/20 see PPalace post

//added 10/23/20 for rear sensor

Rear_Dist_mm = lidar_Rear.readRangeContinuousMillimeters();

Serial.printf("%lu\t%d\t%d\t%d\t%d\t%d\t%d\t%d\n",

millis(), RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, Rear_Dist_mm);

delay(100);

//03/25/21 see if any VL53L0X responds to a query at the default address

Wire1.beginTransmission(DEFAULT_VL53L0X_ADDR);

if (!Wire1.endTransmission() != 0)

{

Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire1!\n", DEFAULT_VL53L0X_ADDR);

InitAllSensors();

}

Wire2.beginTransmission(DEFAULT_VL53L0X_ADDR);

if (!Wire2.endTransmission() != 0)

{

Serial.printf("Ooops! found a VL53L0X sensor at %x on Wire2!\n", DEFAULT_VL53L0X_ADDR);

InitAllSensors();

}

// function that executes whenever data is requested by master

// this function is registered as an event, see setup()

void requestEvent()

{

//Purpose: Send requested sensor data to the Mega controller via main I2C bus

//Inputs:

// request_type = uint8_t value denoting type of data requested (from receiveEvent())

// 0 = left & right center distances only

// 1 = right side front, center and rear distances, plus steering value

// 2 = left side front, center and rear distances, plus steering value

// 3 = both side front, center and rear distances, plus both steering values

//Outputs:

// Requested data sent to master

//Notes:

// 08/05/20 added VL53L0X_ALL request type to get both sides at once

// 10/24/20 added VL53L0X_REAR_ONLY request type

// 11/09/20 added write to pin for O'scope monitoring

// 02/01/21 aded LED_PIN blink

//DEBUG!!

//Serial.printf("RequestEvent() with request_type = %d: VL53L0X Front/Center/Rear distances = %d, %d, %d\n",

// request_type, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm);

//DEBUG!!

digitalWrite(REQUEST_EVENT_DURATION_OUTPUT_PIN, HIGH);

digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));

switch (request_type)

{

case VL53L0X_READYCHECK: //added 11/10/20 to prevent bad reads during Teensy setup()

Serial.printf("in VL53L0X_READYCHECK case at %lu with bTeensyReady = %d\n", millis(), bTeensyReady);

I2C_writeAnything(bTeensyReady);

break;

case VL53L0X_CENTERS_ONLY:

//DEBUG!!

//data_size = 2*sizeof(uint16_t);

//Serial.printf("Sending %d bytes LC_Dist_mm = %d, RC_Dist_mm = %d to master\n", data_size, LC_Dist_mm, RC_Dist_mm);

//DEBUG!!

I2C_writeAnything(RC_Dist_mm);

I2C_writeAnything(LC_Dist_mm);

break;

case VL53L0X_RIGHT:

//DEBUG!!

//data_size = 3 * sizeof(uint16_t) + sizeof(float);

//Serial.printf("Sending %d bytes RF/RC/RR/RS vals = %d, %d, %d, %3.2f to master\n",

// data_size, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, RightSteeringVal);

//DEBUG!!

I2C_writeAnything(RF_Dist_mm);

I2C_writeAnything(RC_Dist_mm);

I2C_writeAnything(RR_Dist_mm);

I2C_writeAnything(RightSteeringVal);

break;

case VL53L0X_LEFT:

//DEBUG!!

//data_size = 3 * sizeof(uint16_t) + sizeof(float);

//Serial.printf("Sending %d bytes LF/LC/LR/LS vals = %d, %d, %d, %3.2f to master\n",

// data_size, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, LeftSteeringVal);

//DEBUG!!

I2C_writeAnything(LF_Dist_mm);

I2C_writeAnything(LC_Dist_mm);

I2C_writeAnything(LR_Dist_mm);

I2C_writeAnything(LeftSteeringVal);

break;

case VL53L0X_ALL:

//added 08/05/20 to get data from both sides at once

//10/31/20 chg to VL53L0X_ALL & report all 7 sensor values

//DEBUG!!

//data_size = 3 * sizeof(uint16_t) + sizeof(float);

//Serial.printf("Sending %d bytes LF/LC/LR/LS vals = %d, %d, %d, %3.2f to master\n",

// data_size, LF_Dist_mm, LC_Dist_mm, LR_Dist_mm, LeftSteeringVal);

//Serial.printf("left %d\t%d\t%d\t%d\t%2.3f",

// LF_Dist_mm, LC_Dist_mm, LR_Dist_mm);

//DEBUG!!

//Serial.printf("In VL53L0X_ALL case\n");

//left side

I2C_writeAnything(LF_Dist_mm);

I2C_writeAnything(LC_Dist_mm);

I2C_writeAnything(LR_Dist_mm);

I2C_writeAnything(LeftSteeringVal);

//DEBUG!!

//data_size = 3 * sizeof(uint16_t) + sizeof(float);

//Serial.printf("Sending %d bytes RF/RC/RR/RS vals = %d, %d, %d, %3.2f to master\n",

// data_size, RF_Dist_mm, RC_Dist_mm, RR_Dist_mm, LeftSteeringVal);

//Serial.printf(" right %d\t%d\t%d\t%d\t%2.3f\n",

//RF_Dist_mm, RC_Dist_mm, RR_Dist_mm);

//DEBUG!!

//right side

I2C_writeAnything(RF_Dist_mm);

I2C_writeAnything(RC_Dist_mm);

I2C_writeAnything(RR_Dist_mm);

I2C_writeAnything(RightSteeringVal);

//10/31/20 now also reporting rear sensor value

I2C_writeAnything(Rear_Dist_mm);

break;

case VL53L0X_REAR_ONLY:

//DEBUG!!

//data_size = sizeof(uint16_t);

//Serial.printf("Sending %d bytes Rear_Dist_mm = %d to master\n", data_size, Rear_Dist_mm);

//DEBUG!!

I2C_writeAnything(Rear_Dist_mm);

break;

default:

break;

}

digitalWrite(REQUEST_EVENT_DURATION_OUTPUT_PIN, LOW);

}

// handle Rx Event (incoming I2C data)

void receiveEvent(int numBytes)

{

//Purpose: capture data request type from Mega I2C master

//Inputs:

// numBytes = int value denoting number of bytes received from master

//Outputs:

// uint8_t request_type filled with request type value from master

//DEBUG!!

//Serial.printf("receiveEvent(%d)\n", numBytes);

//DEBUG!!

I2C_readAnything(request_type);

//DEBUG!!

//Serial.printf("receiveEvent: Got %d from master\n", request_type);

//DEBUG!!

}

bool InitAllSensors()

{

//Purpose: Initialize all seven VL53L0X sensors

//Provenance: 03/22/21

Serial.printf("Initializing VL53L0X Sensor Array Elements\n");

//Put all sensors in reset mode by pulling XSHUT low

digitalWrite(RF_XSHUT_PIN, LOW);

digitalWrite(RC_XSHUT_PIN, LOW);

digitalWrite(RR_XSHUT_PIN, LOW);

digitalWrite(LF_XSHUT_PIN, LOW);

digitalWrite(LC_XSHUT_PIN, LOW);

digitalWrite(LR_XSHUT_PIN, LOW);

//added 10/23/20 for rear sensor

pinMode(Rear_XSHUT_PIN, OUTPUT);

digitalWrite(Rear_XSHUT_PIN, LOW);

//now bring lidar_RF only out of reset and set it's address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RF_XSHUT_PIN, INPUT);

delay(10);

bool retval = true;

if (!lidar_RF.init())

{

Serial.println("Failed to detect and initialize lidar_RF!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RF.setMeasurementTimingBudget(20000);

lidar_RF.startContinuous();

lidar_RF.setAddress(DEFAULT_VL53L0X_ADDR + 1);

Serial.printf("lidar_RF address is 0x%x\n", lidar_RF.getAddress());

delay(100);

//now bring lidar_RC only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RC_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_RC.init())

{

Serial.println("Failed to detect and initialize lidar_RC!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RC.setMeasurementTimingBudget(20000);

lidar_RC.startContinuous();

lidar_RC.setAddress(DEFAULT_VL53L0X_ADDR + 2);

Serial.printf("lidar_RC address is 0x%x\n", lidar_RC.getAddress());

delay(100);

//now bring lidar_RR only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(RR_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_RR.init())

{

Serial.println("Failed to detect and initialize lidar_RR!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_RR.setMeasurementTimingBudget(20000);

lidar_RR.startContinuous();

lidar_RR.setAddress(DEFAULT_VL53L0X_ADDR + 3);

Serial.printf("lidar_RR address is 0x%x\n", lidar_RR.getAddress());

delay(100);

//now bring lidar_LF only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LF_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_LF.init())

{

Serial.println("Failed to detect and initialize lidar_LF!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LF.setMeasurementTimingBudget(20000);

lidar_LF.startContinuous();

lidar_LF.setAddress(DEFAULT_VL53L0X_ADDR + 4);

Serial.printf("lidar_LF address is 0x%x\n", lidar_LF.getAddress());

delay(100);

//now bring lidar_LC only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LC_XSHUT_PIN, INPUT);

delay(10);

if (!lidar_LC.init())

{

Serial.println("Failed to detect and initialize lidar_LC!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LC.setMeasurementTimingBudget(20000);

lidar_LC.startContinuous();

lidar_LC.setAddress(DEFAULT_VL53L0X_ADDR + 5);

Serial.printf("lidar_LC address is 0x%x\n", lidar_LC.getAddress());

delay(100);

//now bring lidar_LR only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(LR_XSHUT_PIN, INPUT);

if (!lidar_LR.init())

{

Serial.println("Failed to detect and initialize lidar_LR!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_LR.setMeasurementTimingBudget(20000);

lidar_LR.startContinuous();

lidar_LR.setAddress(DEFAULT_VL53L0X_ADDR + 6);

Serial.printf("lidar_LR address is 0x%x\n", lidar_LR.getAddress());

delay(100);

//added 10/23/20 for rear sensor

//now bring lidar_Rear only out of reset, initialize it, and set its address

//input w/o pullups sets line to high impedance so XSHUT pullup to 3.3V takes over

pinMode(Rear_XSHUT_PIN, INPUT);

if (!lidar_Rear.init())

{

Serial.println("Failed to detect and initialize lidar_Rear!");

//while (1) {}

retval = false;

}

//from Pololu forum post

lidar_Rear.setMeasurementTimingBudget(20000);

lidar_Rear.startContinuous();

lidar_Rear.setAddress(DEFAULT_VL53L0X_ADDR + 7);

Serial.printf("lidar_Rear address is 0x%x\n", lidar_Rear.getAddress());

return retval;

}

After getting everything set up, I started experimenting. The first thing I tried was momentarily disconnecting one or the other of the two I2C bus connections at the Teensy end. This was interesting in that the affected sensor array results became invalid as soon as the I2C connection was pulled, but resumed valid output as soon as the connection was restored – nice!

Next, I tried momentarily disconnecting the +V line to the arrays. All sensor outputs immediately became invalid, and stayed invalid after +V was restored. In addition, the code in loop() designed to detect one or more VL53L0X sensors at the default address immediately triggered – nice – but the re-initialization code failed to restore valid output.

Here’s the output from a run were the +V line was momentarily disconnected and then reconnected:

Opening port
Port open
Initializing VL53L0X Sensor Array Elements
lidar_RF address is 0x2a
lidar_RC address is 0x2b
lidar_RR address is 0x2c
lidar_LF address is 0x2d
lidar_LC address is 0x2e
lidar_LR address is 0x2f
lidar_Rear address is 0x30
Just after InitAllSensors()
Msec	LFront	LCtr	LRear	RFront	RCtr	RRear	LSteer	RSteer	Rear
6448	373	350	363	544	8191	8190	996
6556	369	344	353	486	8191	8191	1006
6665	371	353	368	475	8191	8190	988
6773	379	352	365	510	512	8190	991
6881	377	346	363	489	8191	8191	1009
6990	368	353	365	541	8191	8191	997
7098	375	350	372	487	8191	8191	989
7206	356	350	366	497	535	8190	983
7315	360	358	364	483	543	8190	997
7423	370	353	363	502	633	8190	1001
7531	373	335	350	465	8191	8190	982
7639	374	349	352	483	497	8191	1017
7748	356	350	381	503	8191	8190	1000
7856	362	350	364	489	585	8191	1013
7964	359	346	380	477	557	8191	979
8073	357	350	361	482	8191	8190	1019
8181	357	347	367	463	8191	8191	1011
8289	374	349	359	459	8191	8190	996
8397	363	348	371	494	8191	8191	1030
8506	365	351	370	557	509	8191	1000
8614	367	345	368	480	445	8191	974
8722	364	354	365	500	8191	8190	987
8831	384	349	356	524	470	8190	1019
8939	376	348	363	539	534	8191	1007
9047	354	349	371	522	475	8191	1020
9156	369	353	362	758	8191	8190	1003
9264	361	347	380	489	8191	8190	981
9372	364	350	367	463	8191	8190	998
9480	366	350	375	505	498	8190	985
9589	382	346	364	445	8191	8190	1004
9697	365	346	373	484	492	8190	996
9805	375	349	353	493	616	8190	1004
9914	371	349	356	538	492	8191	1001
10022	379	346	366	496	503	8191	1016
10130	365	349	354	446	428	8190	1025
10239	381	347	366	474	8191	8191	1008
10347	372	351	362	493	647	8191	1006
10455	366	344	358	487	8191	8191	987
10563	379	346	367	487	566	8191	979
10672	370	348	366	496	8191	8191	975
10780	375	356	360	510	601	8191	1000
10888	370	343	370	497	550	8191	1006
10997	371	352	360	488	8191	8190	982
11105	369	351	353	501	8191	8191	1019
11213	370	345	363	483	8191	8190	1020
11321	372	349	361	503	561	8190	1023
11430	369	351	379	505	453	8191	976
11538	373	347	366	495	8191	8191	988
11646	364	351	372	488	8191	8191	989
11755	365	339	361	470	544	8191	1011
11863	374	358	369	483	8191	8191	1008
11971	367	343	370	490	499	8190	1013
12080	364	348	373	475	491	8191	1006
12188	367	344	363	495	8191	8190	1025
12296	376	349	362	514	580	8191	1035
12404	366	351	365	474	8191	8190	1021
12513	364	350	372	489	8191	8191	1004
12621	373	348	357	494	8191	8190	998
12729	371	352	364	523	8191	8191	1015
12838	365	355	372	500	8191	8190	987
12946	364	357	374	497	8191	8190	998
13054	365	347	364	520	436	8190	990
13163	364	351	381	535	8191	8191	1028
13271	366	345	375	499	8191	8191	1011
13379	358	350	356	482	705	8190	1008
13487	366	350	365	532	590	8191	1008
13596	370	349	355	491	563	8190	1021
13704	364	348	368	517	480	8190	1018
13812	358	348	375	481	8191	8191	1014
13921	363	346	359	503	8191	8191	1004
14029	371	353	363	458	8191	8191	983
14137	376	357	357	565	641	8191	999
14246	360	348	368	548	535	8191	1021
14354	364	347	367	494	601	8191	1002
14462	364	352	372	470	550	8191	991
14570	366	349	366	532	536	8191	1003
14679	374	348	364	493	520	8191	1000
14787	364	345	363	471	8191	8191	1000
14895	364	341	371	503	8191	8190	994
15004	360	349	366	474	605	8191	1030
15112	375	342	356	464	548	8190	986
15220	367	351	364	471	524	8190	1022
15328	365	349	372	491	656	8191	1001
15437	364	347	365	472	8191	8191	993
15545	366	348	365	520	8191	8191	980
15653	374	348	361	527	591	8191	1010
15762	363	352	361	500	609	8190	1002
15870	370	352	370	531	8191	8191	1004
15978	367	353	365	555	8191	8191	987
16087	366	348	365	501	8191	8191	992
16195	366	347	362	481	558	8190	1013
16303	368	352	364	485	8191	8190	1018
16411	372	340	360	459	8003	8191	993
16520	366	357	369	503	561	8191	1009
16628	365	345	364	416	497	8191	986
16736	363	352	362	542	8191	8191	996
16845	373	356	365	455	8191	8190	975
16953	354	342	364	488	551	8191	971
17061	368	349	364	495	8191	8191	983
17170	371	350	367	451	421	8191	1019
17278	367	345	362	465	8191	8190	977
17386	369	351	367	517	604	8190	990
17494	371	342	363	513	8191	8190	999
17603	368	350	365	498	8191	8191	986
17711	362	350	371	509	600	8190	988
17819	366	351	360	515	8191	8190	1002
17928	378	348	364	478	8191	8190	999
18036	367	346	365	436	8191	8191	1035
18144	378	349	356	515	596	8190	1017
18253	365	347	364	491	8191	8191	1018
18361	370	349	367	478	649	8191	1024
18469	370	348	366	443	8191	8190	1002
18577	374	345	366	471	8191	8190	1009
18686	370	355	372	499	8191	8191	1022
18794	362	353	364	480	8191	8191	1003
18902	368	347	365	507	510	8191	1007
19011	373	357	367	486	8191	8190	1029
19119	369	351	362	498	8191	8190	999
19227	360	347	365	445	8191	8190	995
19336	363	351	371	471	557	8190	985
19444	364	354	368	439	707	8190	985
19552	360	354	371	529	8191	8190	994
19660	358	351	373	496	438	8191	992
19769	363	348	366	457	8191	8190	1000
19877	361	358	368	435	689	8190	1005
19985	364	351	371	500	8191	8191	996
20094	368	351	363	478	8191	8190	1029
20202	365	351	370	521	8191	8191	996
20310	373	345	365	514	8191	8191	1009
20418	368	348	367	526	596	8191	959
20527	369	351	351	534	8191	8191	1011
20635	373	346	361	512	8191	8190	989
20743	367	349	367	470	8191	8190	1023
20852	364	344	354	443	586	8191	1027
20960	369	353	375	481	8191	8191	1010
21068	372	354	369	471	461	8190	999
21177	369	353	364	509	8191	8191	977
21285	372	351	366	516	517	8191	1013
21393	370	355	351	515	673	8190	1018
21501	366	351	366	481	8191	8190	1037
21610	374	353	371	547	478	8191	1006
21718	367	354	369	492	8191	8190	991
21826	368	347	359	454	664	8191	982
21935	362	347	370	530	635	8190	997
22043	368	350	368	523	488	8190	984
22151	364	352	363	539	8191	8191	1032
22260	362	348	355	552	8191	8190	995
22368	375	348	357	528	616	8191	996
22476	371	349	357	491	679	8191	1020
22584	370	352	363	539	517	8190	1007
22693	367	346	360	491	8191	8191	1015
22801	366	348	373	524	8191	8190	1003
22909	381	346	371	498	682	8191	1027
23018	373	345	367	528	587	8190	1024
23126	369	341	364	482	8191	8191	1021
23234	372	344	365	532	8191	8190	983
23343	369	352	363	457	8191	8191	1012
23451	370	345	360	448	590	8191	997
23559	364	348	380	523	570	8190	996
23667	378	346	368	509	492	8191	1002
23776	370	348	375	473	8191	8190	1004
23884	371	344	365	457	8191	8190	1001
23992	368	350	375	469	8191	8190	1027
24101	376	353	361	484	8191	8190	1009
24209	373	348	374	529	8191	8190	1015
24317	375	352	368	559	8191	8190	973
24426	369	354	370	541	8191	8191	1003
24534	361	345	366	510	8191	1143	987
24642	364	350	363	420	857	8191	982
24750	367	345	364	496	8191	8190	1021
24859	362	344	370	482	8191	8191	1010
24967	366	346	367	420	503	8191	1005
25075	361	349	372	383	447	8191	981
25184	369	343	371	393	386	8190	1003
25292	367	355	374	360	395	8191	1016
25400	369	342	367	368	392	408	1008
25508	360	352	375	374	376	431	1020
25617	364	355	371	368	352	369	1022
25725	364	346	368	364	322	328	1016
25833	362	348	376	381	320	284	1000
25942	368	343	362	402	331	279	1030
26050	367	352	361	411	333	264	1011
26158	366	349	371	399	364	279	1008
26267	361	356	378	390	367	291	997
26375	365	350	370	373	369	306	1002
26483	372	349	357	367	353	306	980
26591	369	350	371	355	340	300	1002
26700	362	348	372	339	340	297	998
26808	370	353	372	338	325	295	1015
26916	371	351	368	341	331	287	1011
27025	362	344	370	338	325	287	994
27133	369	350	357	334	319	292	1000
27241	371	347	365	328	303	293	972
27349	373	352	365	318	310	293	1013
27458	359	352	374	321	302	283	999
27566	366	347	360	311	308	277	1004
27674	370	348	368	321	303	285	1024
27783	369	349	365	320	315	282	1036
27891	371	352	364	316	307	279	1006
27999	369	346	361	326	295	282	989
28108	367	350	359	312	301	279	1001
28216	373	345	373	315	299	279	1006
28324	368	362	364	306	302	274	989
28432	367	346	365	320	303	284	1025
28541	370	355	363	313	306	277	1003
28649	378	347	369	317	295	280	997
28757	368	348	364	324	307	274	1011
28866	377	349	362	330	300	285	1007
28974	371	352	366	326	307	291	998
29104	65535	65535	65535	65535	65535	65535	65535
29224	65535	65535	65535	65535	65535	65535	65535
29418	65535	65535	65535	65535	65535	65535	65535
Ooops! found a VL53L0X sensor at 29 on Wire1!
Initializing VL53L0X Sensor Array Elements
Failed to detect and initialize lidar_RF!
lidar_RF address is 0x2a
Failed to detect and initialize lidar_RC!
lidar_RC address is 0x2b
Failed to detect and initialize lidar_RR!
lidar_RR address is 0x2c
Failed to detect and initialize lidar_LF!
lidar_LF address is 0x2d
Failed to detect and initialize lidar_LC!
lidar_LC address is 0x2e
Failed to detect and initialize lidar_LR!
lidar_LR address is 0x2f
Failed to detect and initialize lidar_Rear!
lidar_Rear address is 0x30
Ooops! found a VL53L0X sensor at 29 on Wire2!
30190	65535	65535	65535	65535	65535	65535	65535
Ooops! found a VL53L0X sensor at 29 on Wire1!
Initializing VL53L0X Sensor Array Elements
Failed to detect and initialize lidar_RF!
lidar_RF address is 0x2a
Failed to detect and initialize lidar_RC!
lidar_RC address is 0x2b
Failed to detect and initialize lidar_RR!
lidar_RR address is 0x2c
Failed to detect and initialize lidar_LF!
lidar_LF address is 0x2d
Failed to detect and initialize lidar_LC!
lidar_LC address is 0x2e
Failed to detect and initialize lidar_LR!
lidar_LR address is 0x2f
Failed to detect and initialize lidar_Rear!
lidar_Rear address is 0x30
Ooops! found a VL53L0X sensor at 29 on Wire2!
30962	65535	65535	65535	65535	65535	65535	65535
Ooops! found a VL53L0X sensor at 29 on Wire1!
Initializing VL53L0X Sensor Array Elements
Failed to detect and initialize lidar_RF!
lidar_RF address is 0x2a
Failed to detect and initialize lidar_RC!
lidar_RC address is 0x2b
Failed to detect and initialize lidar_RR!
lidar_RR address is 0x2c
Failed to detect and initialize lidar_LF!
lidar_LF address is 0x2d
Failed to detect and initialize lidar_LC!
lidar_LC address is 0x2e
Failed to detect and initialize lidar_LR!
lidar_LR address is 0x2f
Failed to detect and initialize lidar_Rear!
lidar_Rear address is 0x30

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Opening port

Port open

Initializing VL53L0X Sensor Array Elements

lidar_RF address is 0x2a

lidar_RC address is 0x2b

lidar_RR address is 0x2c

lidar_LF address is 0x2d

lidar_LC address is 0x2e

lidar_LR address is 0x2f

lidar_Rear address is 0x30

Just after InitAllSensors()

Msec LFront LCtr LRear RFront RCtr RRear LSteer RSteer Rear

6448 373 350 363 544 8191 8190 996

6556 369 344 353 486 8191 8191 1006

6665 371 353 368 475 8191 8190 988

6773 379 352 365 510 512 8190 991

6881 377 346 363 489 8191 8191 1009

6990 368 353 365 541 8191 8191 997

7098 375 350 372 487 8191 8191 989

7206 356 350 366 497 535 8190 983

7315 360 358 364 483 543 8190 997

7423 370 353 363 502 633 8190 1001

7531 373 335 350 465 8191 8190 982

7639 374 349 352 483 497 8191 1017

7748 356 350 381 503 8191 8190 1000

7856 362 350 364 489 585 8191 1013

7964 359 346 380 477 557 8191 979

8073 357 350 361 482 8191 8190 1019

8181 357 347 367 463 8191 8191 1011

8289 374 349 359 459 8191 8190 996

8397 363 348 371 494 8191 8191 1030

8506 365 351 370 557 509 8191 1000

8614 367 345 368 480 445 8191 974

8722 364 354 365 500 8191 8190 987

8831 384 349 356 524 470 8190 1019

8939 376 348 363 539 534 8191 1007

9047 354 349 371 522 475 8191 1020

9156 369 353 362 758 8191 8190 1003

9264 361 347 380 489 8191 8190 981

9372 364 350 367 463 8191 8190 998

9480 366 350 375 505 498 8190 985

9589 382 346 364 445 8191 8190 1004

9697 365 346 373 484 492 8190 996

9805 375 349 353 493 616 8190 1004

9914 371 349 356 538 492 8191 1001

10022 379 346 366 496 503 8191 1016

10130 365 349 354 446 428 8190 1025

10239 381 347 366 474 8191 8191 1008

10347 372 351 362 493 647 8191 1006

10455 366 344 358 487 8191 8191 987

10563 379 346 367 487 566 8191 979

10672 370 348 366 496 8191 8191 975

10780 375 356 360 510 601 8191 1000

10888 370 343 370 497 550 8191 1006

10997 371 352 360 488 8191 8190 982

11105 369 351 353 501 8191 8191 1019

11213 370 345 363 483 8191 8190 1020

11321 372 349 361 503 561 8190 1023

11430 369 351 379 505 453 8191 976

11538 373 347 366 495 8191 8191 988

11646 364 351 372 488 8191 8191 989

11755 365 339 361 470 544 8191 1011

11863 374 358 369 483 8191 8191 1008

11971 367 343 370 490 499 8190 1013

12080 364 348 373 475 491 8191 1006

12188 367 344 363 495 8191 8190 1025

12296 376 349 362 514 580 8191 1035

12404 366 351 365 474 8191 8190 1021

12513 364 350 372 489 8191 8191 1004

12621 373 348 357 494 8191 8190 998

12729 371 352 364 523 8191 8191 1015

12838 365 355 372 500 8191 8190 987

12946 364 357 374 497 8191 8190 998

13054 365 347 364 520 436 8190 990

13163 364 351 381 535 8191 8191 1028

13271 366 345 375 499 8191 8191 1011

13379 358 350 356 482 705 8190 1008

13487 366 350 365 532 590 8191 1008

13596 370 349 355 491 563 8190 1021

13704 364 348 368 517 480 8190 1018

13812 358 348 375 481 8191 8191 1014

13921 363 346 359 503 8191 8191 1004

14029 371 353 363 458 8191 8191 983

14137 376 357 357 565 641 8191 999

14246 360 348 368 548 535 8191 1021

14354 364 347 367 494 601 8191 1002

14462 364 352 372 470 550 8191 991

14570 366 349 366 532 536 8191 1003

14679 374 348 364 493 520 8191 1000

14787 364 345 363 471 8191 8191 1000

14895 364 341 371 503 8191 8190 994

15004 360 349 366 474 605 8191 1030

15112 375 342 356 464 548 8190 986

15220 367 351 364 471 524 8190 1022

15328 365 349 372 491 656 8191 1001

15437 364 347 365 472 8191 8191 993

15545 366 348 365 520 8191 8191 980

15653 374 348 361 527 591 8191 1010

15762 363 352 361 500 609 8190 1002

15870 370 352 370 531 8191 8191 1004

15978 367 353 365 555 8191 8191 987

16087 366 348 365 501 8191 8191 992

16195 366 347 362 481 558 8190 1013

16303 368 352 364 485 8191 8190 1018

16411 372 340 360 459 8003 8191 993

16520 366 357 369 503 561 8191 1009

16628 365 345 364 416 497 8191 986

16736 363 352 362 542 8191 8191 996

16845 373 356 365 455 8191 8190 975

16953 354 342 364 488 551 8191 971

17061 368 349 364 495 8191 8191 983

17170 371 350 367 451 421 8191 1019

17278 367 345 362 465 8191 8190 977

17386 369 351 367 517 604 8190 990

17494 371 342 363 513 8191 8190 999

17603 368 350 365 498 8191 8191 986

17711 362 350 371 509 600 8190 988

17819 366 351 360 515 8191 8190 1002

17928 378 348 364 478 8191 8190 999

18036 367 346 365 436 8191 8191 1035

18144 378 349 356 515 596 8190 1017

18253 365 347 364 491 8191 8191 1018

18361 370 349 367 478 649 8191 1024

18469 370 348 366 443 8191 8190 1002

18577 374 345 366 471 8191 8190 1009

18686 370 355 372 499 8191 8191 1022

18794 362 353 364 480 8191 8191 1003

18902 368 347 365 507 510 8191 1007

19011 373 357 367 486 8191 8190 1029

19119 369 351 362 498 8191 8190 999

19227 360 347 365 445 8191 8190 995

19336 363 351 371 471 557 8190 985

19444 364 354 368 439 707 8190 985

19552 360 354 371 529 8191 8190 994

19660 358 351 373 496 438 8191 992

19769 363 348 366 457 8191 8190 1000

19877 361 358 368 435 689 8190 1005

19985 364 351 371 500 8191 8191 996

20094 368 351 363 478 8191 8190 1029

20202 365 351 370 521 8191 8191 996

20310 373 345 365 514 8191 8191 1009

20418 368 348 367 526 596 8191 959

20527 369 351 351 534 8191 8191 1011

20635 373 346 361 512 8191 8190 989

20743 367 349 367 470 8191 8190 1023

20852 364 344 354 443 586 8191 1027

20960 369 353 375 481 8191 8191 1010

21068 372 354 369 471 461 8190 999

21177 369 353 364 509 8191 8191 977

21285 372 351 366 516 517 8191 1013

21393 370 355 351 515 673 8190 1018

21501 366 351 366 481 8191 8190 1037

21610 374 353 371 547 478 8191 1006

21718 367 354 369 492 8191 8190 991

21826 368 347 359 454 664 8191 982

21935 362 347 370 530 635 8190 997

22043 368 350 368 523 488 8190 984

22151 364 352 363 539 8191 8191 1032

22260 362 348 355 552 8191 8190 995

22368 375 348 357 528 616 8191 996

22476 371 349 357 491 679 8191 1020

22584 370 352 363 539 517 8190 1007

22693 367 346 360 491 8191 8191 1015

22801 366 348 373 524 8191 8190 1003

22909 381 346 371 498 682 8191 1027

23018 373 345 367 528 587 8190 1024

23126 369 341 364 482 8191 8191 1021

23234 372 344 365 532 8191 8190 983

23343 369 352 363 457 8191 8191 1012

23451 370 345 360 448 590 8191 997

23559 364 348 380 523 570 8190 996

23667 378 346 368 509 492 8191 1002

23776 370 348 375 473 8191 8190 1004

23884 371 344 365 457 8191 8190 1001

23992 368 350 375 469 8191 8190 1027

24101 376 353 361 484 8191 8190 1009

24209 373 348 374 529 8191 8190 1015

24317 375 352 368 559 8191 8190 973

24426 369 354 370 541 8191 8191 1003

24534 361 345 366 510 8191 1143 987

24642 364 350 363 420 857 8191 982

24750 367 345 364 496 8191 8190 1021

24859 362 344 370 482 8191 8191 1010

24967 366 346 367 420 503 8191 1005

25075 361 349 372 383 447 8191 981

25184 369 343 371 393 386 8190 1003

25292 367 355 374 360 395 8191 1016

25400 369 342 367 368 392 408 1008

25508 360 352 375 374 376 431 1020

25617 364 355 371 368 352 369 1022

25725 364 346 368 364 322 328 1016

25833 362 348 376 381 320 284 1000

25942 368 343 362 402 331 279 1030

26050 367 352 361 411 333 264 1011

26158 366 349 371 399 364 279 1008

26267 361 356 378 390 367 291 997

26375 365 350 370 373 369 306 1002

26483 372 349 357 367 353 306 980

26591 369 350 371 355 340 300 1002

26700 362 348 372 339 340 297 998

26808 370 353 372 338 325 295 1015

26916 371 351 368 341 331 287 1011

27025 362 344 370 338 325 287 994

27133 369 350 357 334 319 292 1000

27241 371 347 365 328 303 293 972

27349 373 352 365 318 310 293 1013

27458 359 352 374 321 302 283 999

27566 366 347 360 311 308 277 1004

27674 370 348 368 321 303 285 1024

27783 369 349 365 320 315 282 1036

27891 371 352 364 316 307 279 1006

27999 369 346 361 326 295 282 989

28108 367 350 359 312 301 279 1001

28216 373 345 373 315 299 279 1006

28324 368 362 364 306 302 274 989

28432 367 346 365 320 303 284 1025

28541 370 355 363 313 306 277 1003

28649 378 347 369 317 295 280 997

28757 368 348 364 324 307 274 1011

28866 377 349 362 330 300 285 1007

28974 371 352 366 326 307 291 998

29104 65535 65535 65535 65535 65535 65535 65535

29224 65535 65535 65535 65535 65535 65535 65535

29418 65535 65535 65535 65535 65535 65535 65535

Ooops! found a VL53L0X sensor at 29 on Wire1!

Initializing VL53L0X Sensor Array Elements

Failed to detect and initialize lidar_RF!

lidar_RF address is 0x2a

Failed to detect and initialize lidar_RC!

lidar_RC address is 0x2b

Failed to detect and initialize lidar_RR!

lidar_RR address is 0x2c

Failed to detect and initialize lidar_LF!

lidar_LF address is 0x2d

Failed to detect and initialize lidar_LC!

lidar_LC address is 0x2e

Failed to detect and initialize lidar_LR!

lidar_LR address is 0x2f

Failed to detect and initialize lidar_Rear!

lidar_Rear address is 0x30

Ooops! found a VL53L0X sensor at 29 on Wire2!

30190 65535 65535 65535 65535 65535 65535 65535

Ooops! found a VL53L0X sensor at 29 on Wire1!

Initializing VL53L0X Sensor Array Elements

Failed to detect and initialize lidar_RF!

lidar_RF address is 0x2a

Failed to detect and initialize lidar_RC!

lidar_RC address is 0x2b

Failed to detect and initialize lidar_RR!

lidar_RR address is 0x2c

Failed to detect and initialize lidar_LF!

lidar_LF address is 0x2d

Failed to detect and initialize lidar_LC!

lidar_LC address is 0x2e

Failed to detect and initialize lidar_LR!

lidar_LR address is 0x2f

Failed to detect and initialize lidar_Rear!

lidar_Rear address is 0x30

Ooops! found a VL53L0X sensor at 29 on Wire2!

30962 65535 65535 65535 65535 65535 65535 65535

Ooops! found a VL53L0X sensor at 29 on Wire1!

Initializing VL53L0X Sensor Array Elements

Failed to detect and initialize lidar_RF!

lidar_RF address is 0x2a

Failed to detect and initialize lidar_RC!

lidar_RC address is 0x2b

Failed to detect and initialize lidar_RR!

lidar_RR address is 0x2c

Failed to detect and initialize lidar_LF!

lidar_LF address is 0x2d

Failed to detect and initialize lidar_LC!

lidar_LC address is 0x2e

Failed to detect and initialize lidar_LR!

lidar_LR address is 0x2f

Failed to detect and initialize lidar_Rear!

lidar_Rear address is 0x30

28 March 2021 Update:

I have been continuing to work on the ‘re-initialize after power interruption’ idea for my VL53L0X sensor array, and while I haven’t come up with a very good solution, I have learned some things:

The VL53L0X reverts to it’s default (0x29) I2C address immediately when power is removed, but will actually respond to a 0x29 query even after power has been removed. Apparently, the module can draw enough current from the I2C connections to continue to operate (albeit at the default address).
A ‘powered down’ (power disconnected, but I2C leads still connected) will also respond to distance measurement requests, but will return a nonsense number (65535).
In order to get a VL53L0X sensor to stop responding, the power lead must be physically grounded – just disconnecting isn’t enough.
If I use a digital output to power the array, I can turn the power on and off programmatically. Using this tool:
- Turning power OFF causes distance measurements to return ‘65535’ (because this is the same as connecting the power lead to GND). However, this isn’t the normal failure mode; the normal failure mode for power disconnections is an open-circuit – not GND
- Turning power back ON again causes the system to detect that one or more VL53L0X units has appeared at the default I2C address. This probably means I could successfully re-initialize all modules.

So, it looks like I can’t really protect against an arbitrary length power disconnect scenario, as I can’t tell when the power has been restored. All I can do is have the program detect the ‘65535’ distance value, wait for some time (a few seconds?) and then try to re-initialize the sensors. This is, unfortunately, a one-shot deal, as if power hasn’t been restored when the re-init procedure is executed, the initialization code hangs up permanently.

Stay tuned!

Frank

Paynter's Palace

Tag Archives: DipTrace

Wall-E3 Replacing Mega 2560 With Teensy 3.5 Part VII

13 February 2022 Update:

09 March 2022 Update:

11 March 2022:

02 April 2022 Update:

Wall-E2 Gets a VL53L0X Array Upgrade

25 March 2021 Update:

28 March 2021 Update: