I2C

The micro:bit has 2 I2C devices the  accelerometer and magnetometer. the address of the devices are as follows

Now you can also connect I2C devices to your micro:bit and sometimes you need to check the address of the device or this can also be used as a useful debug tool to make sure your device is detected.

There are 2 ways of doing this here, the first is in python using the mu editor and the next one is using an Arduino

Code

[codesyntax lang=”python”]

from microbit import *

start = 0x07
end = 0x70

while True:
    display.show(Image.ARROW_W)
    if button_a.was_pressed():
        display.show(Image.SMILE)
        print("Scanning I2C bus...")
        for i in range(start, end + 1):
            try:
                i2c.read(i, 1)
            except OSError:
                pass
            else:
                print("Found:  [%s]" % hex(i))
        print("Scanning complete")
    sleep(10)

[/codesyntax]

 

 

Now look at the REPL

>>> Scanning I2C bus…

Found: [0xe]

Found: [0x1d]

Scanning complete

Magnetometer [0x0e] Accelerometer [0x1d]

 

Now for the Arduino version

[codesyntax lang=”cpp”]

#include <Wire.h>
 
void setup()
{
  Wire.begin();
  Serial.begin(9600);
  Serial.println("\nI2C Scanner");
}
 
 
void loop()
{
  byte error, address;
  int nDevices;
 
  Serial.println("Scanning...");
 
  nDevices = 0;
  for(address = 1; address < 127; address++ )
  {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
 
    if (error == 0)
    {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");
 
      nDevices++;
    }
    else if (error==4)
    {
      Serial.print("Unknown error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");
 
  delay(5000);           // wait 5 seconds for next scan
}

[/codesyntax]

 

Open the serial monitor and you should see something like this

Scanning…
I2C device found at address 0x0E !
I2C device foun!
I2C device found at address 0x1D !
done