Problem with multiple sensors (3) on the I2C bus and C++ API

[userLM]

Hi ST team and community !

I'm here because i have some troubles on the processus of initialisation of multiple sensors VL53L1CB.

I use the following library available on gitHub : https://github.com/stm32duino/VL53L1

The processus is the following :

• Shut down reset pin XSHUT of each sensor

Then, in a for loop (to setup my 3 sensors) :

• Power ON the first sensor with XSHUT pin
• I2C scanner to detect my only sensor ON (normally at address 0x29)
• Create my C++ component with the I2C link and XSHUT digital/analog PIN
• Init sensor with the new address with InitSensor function in the class VL53L1 of C++ API
• I2C scanner again to check if the address has been changed

Then, switch to another sensor in the for loop until initialisation of my 3 sensors.

My problem is when the for loop arrives on the third sensor, it's impossible to execute InitSensor function and the program turn to infinity.

Question is, there is a RAM probleme when i create C++ component with "new/delete" ? (load the entire VL53L1 class ?) I have 32KB of RAM

Do you have some exemple of multiple VL53L1CB (not VL53L1X) initialisation with C++ API ?

Here is my code :

const int numberOfSensor = 3;                                 
uint8_t devAddr[3] = {0x62, 0x64, 0x66};                       
VL53L1 *nVL53L1[numberOfSensor];                    
int sensor = 0;              
static const uint8_t XSHUT[3] = {0,1,2};             
 
void setup()
{
   // Initialize serial for output.
   delay(5000);
   SerialPort.begin(115200);
   SerialPort.println("Starting...");
 
   // Initialize I2C bus.
   DEV_I2C.begin();
   DEV_I2C.setClock(400000); // 400KHz
   SerialPort.println("Start I2C : ok");
 
   // XSHUT declarer en sortie et mis au niveau bas
   pinMode(XSHUT[0], OUTPUT);
   pinMode(XSHUT[1], OUTPUT);
   pinMode(XSHUT[2], OUTPUT);
   digitalWrite(XSHUT[0], LOW);
   digitalWrite(XSHUT[1], LOW);
   digitalWrite(XSHUT[2], LOW);
   SerialPort.println("ALL XSHUT OUTPUT DOWN : ok");
   
   // Initialize VL53L1 satellite component.
   for (sensor=0; sensor<numberOfSensor; sensor++)
   {
      // SHUT ON reset pin of sensor
      digitalWrite(XSHUT[sensor], HIGH);
      SerialPort.println("XSHUT UP"+String(sensor)+" : ok");
 
      // Search all addr connected to my SAMD21
      debug_I2C_scanner();
      SerialPort.println("Scanner I2C : ok");
 
      // Create VL53L1 satellite component
      nVL53L1[sensor] = new VL53L1(&DEV_I2C, XSHUT[sensor]);
      SerialPort.println("Create component : ok");
      
      status += nVL53L1[sensor]->InitSensor(devAddr[sensor]); 
      SerialPort.println("Statut initialisation : "+String(status));
 
      //  Search all addr connected to my SAMD21 to check
      debug_I2C_scanner();
      SerialPort.println("Scanner I2C check : ok"); 
   }
}

(I call the delete just after)

There is the result in the shell of the execution :

//START
 
Starting...
Start I2C : ok
ALL XSHUT OUTPUT DOWN : ok
XSHUT UP0 : ok
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x29  !
done
 
Scanner I2C : ok
Create component : ok
Statut Initialisation : 0
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x31  !
done
 
Scanner I2C check : ok
 
XSHUT UP1 : ok
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x29  ! // NEW SENSOR ON
I2C device found at address 0x31  !
done
 
Scanner I2C : ok
Create component : ok
Statut Initialisation : 0
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x31  !
I2C device found at address 0x32  !
done
 
Scanner I2C check : ok
 
XSHUT UP2 : ok
Scanning...
I2C device found at address 0x19  !
I2C device found at address 0x1E  !
I2C device found at address 0x29  ! //NEW SENSOR ON
I2C device found at address 0x31  !
I2C device found at address 0x32  !
done
 
Scanner I2C : ok
 
//STOP

I need help ! I don't understand...

If there any C++ dev in the community, don't hesit to tell me what's my error.

Best regards,

LM

[John E KVAM]

I have a superstition. It bothers the heck out of me when the I2C addresses are next to each other.

In all my code I use address 29- the default, and then change them to 39, 49, 59 and so on.

I know it makes no sense. You should be able to use all the addresses.

But I've never had luck with it.

In your code you changed the 29 to 32.

I recommend trying it again and avoid the even addresses at the very least.

But perhaps someone else will have a better idea.

As for you suggestion that there might be a ram problem, are you using a particularly small MCU?

• john

[userLM · Accepted solution]

Hi John,

Thanks for your fast answer !

I use uint8_t devAddr[3] = {0x62, 0x64, 0x66};

Those adresses are divided by 2 in the function VL53L1_SetDeviceAddress(address) (include in the function InitSensor(uint8_t address)) that's why i have 0x31, 0x32 ...

I will try to change these addresses by {0x62, 0x66, 0x70} to have finally 0x31, 0x33, 0x35 if i understood well

I have 32KB of RAM, it's not enought ?

If my dev is right, with a sizeof of the main class VL53L1, i obtain 10800 bytes. So, 10,8*3=32.4 KB, so i overload my memory i'am right ? If yes, do you try to use modern C++ function like unique_ptr, make_unique and shared_ptr to share the class to differents objets defines on the same I2C bus ?

With those methode, we can maybe just create 1 call of the main class and share this class to 3 differents sensors... i will think about it !

LM