No Wire.endTransmission() needed after Wire.requestFrom().

[dfrobot]

No Wire.endTransmission() needed after Wire.requestFrom().

[forKnowYou]

Sorry for late reply.
It's my pleasure to receive your advise.
We have tested and found that the library cannot read registers when the sentence been removed.

[Koepel]

I mean the last Wire.endTransmission(); in the function readReg(), not the one that is used to write the register address to the chip.

Are you saying that reading the registers before that line can not be done if that line is removed ?

The Wire.endTransmission() should only be used when writing data. It should not be used after a Wire.requestFrom(). That is how the Wire library works. That is how the documentation is.

In case you did remove the right line: It will cause an extra delay, perhaps that is needed. When the Wire library for AVR chips is used, a Wire.endTransmission() on its own puts the sensor address on the I2C bus and the sensor acknowledges that. However, that behaviour can change since it is not documented and should not be used like that.

[forKnowYou]

You mean the line 106 in DFRobot_BME680.cpp right?
We had try to removed it, and it looks like BME680 need that single.
I am a yong engineer, thanks for your explanation. I will do more exploration.

[Koepel]

No, line 112.
That is after the Wire.requestFrom().

To write data, the functions Wire.beginTransmission, Wire.write and Wire.endTransmission are used. Those three belong together.
To read data, only the function Wire.requestFrom is used. After that, Wire.available and/or Wire.read can be used, but Wire.requestFrom does the complete I2C transaction on its own.

[forKnowYou]

Understood, thanks.

[Koepel]

I see the issue has been solved. I will close this issue.