Strange error from Wire.endTransimmsion() on LSM6DS0

Using Arduino Networking, Protocols, and Devices
1

Hello,
I try to use the Sprakfun LSM6DS0 breakout, but I got errors interfacing with it.
I quickly saw that I can get acceleration values and temperature, but not gyro data.
Investigating in the problem, I discovered the problem comes from I2C communication.
The board is connected to an ESP32 FireBeetle.
I already used this board with a Sparkfun ICM-20948 breakout but looking at the library, I saw that I2C errors are not checked so, maybe I also have the problem, didn't check, but that works.

So, back to my problem with the LSM6DS0, I Investigated a bit deeper with the following code, which is equivalent to imu.getAccelDataRate()call.

void loop()
{
  uint8_t status;
  uint8_t regVal;
  
  blinkState = !blinkState;
  digitalWrite(LED_BUILTIN, blinkState);

  Wire.beginTransmission(0x6B);
  Wire.write(CTRL1_XL);
  if( (status = Wire.endTransmission(false)) != 0 ) {
    Serial.print("Status1 : ");
    Serial.println(status, HEX);
  }

  Wire.requestFrom(0x6B, 1);
  regVal =  Wire.read(); 

  if( (status = Wire.endTransmission()) != 0 ) {
    Serial.print("Status2 : ");
    Serial.println(status, HEX);
  }

  Serial.println(regVal, DEC);
}

And the result is:

status2 = 8
120

So clearly, the problem comes from call to Wire.endTransmission()only, not Wire.endTransmission(false).

But according to Arduino doc, returns of Wire.endTransmission() can be one of:

  • 0:success
  • 1:data too long to fit in transmit buffer
  • 2:received NACK on transmit of address
  • 3:received NACK on transmit of data
  • 4:other error

Nothing about error code 8.

So, I don't really understand what happens here.

Globally, communication works, but something is bad anyway and because of that, I suspect some initialization code fails and gyro may be not enabled.

Any idea?

2

Are you sure the results you're sharing are from the code you shared?

3

What makes you think that a Wire.requestFrom() should be followed by a Wire.endTransmission()?

1 Like
4

Sparkfun LSM6DSO module: https://www.sparkfun.com/products/18020.
Sparkfun LSM6DSO library: https://github.com/sparkfun/SparkFun_Qwiic_6DoF_LSM6DSO_Arduino_Library

So I'm reading the code of the library and then :face_vomiting: O no, not again, and it is recent code from Sparkfun :man_facepalming:
Here we go again, yet another Issue about the Wire library on Github: https://github.com/sparkfun/SparkFun_Qwiic_6DoF_LSM6DSO_Arduino_Library/issues/2

My Issue answers the question by @DrDiettrich
I don't know if that fixes the problem with the gyro data, perhaps there are more bugs in it.

5

They will never learn, but some of their stuff is OK.

6

What other thing can set status?

7

Oh, good to know, I test it.

8

Wire.requestFrom() returns the number of bytes received. If it is the requested count then everything is okay.

1 Like
9

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