Question about the Feather Battery I2C Shield


Hi folks,

Just got this: I2C shield
My question is: is there any documentation about this board? The board looks very nice built, top quality made in USA. But I like to know more about it. For example, there is an IC or something like sensor, next to it is: U1
What is this sensor or IC suppose to do?

Any help or documentation will be appreciated.

Thanks a lot,
Alex Rodriguez


Hi Alex,
That ic is a regulator and it will boost the voltage from 3.3V to 5V. This 5Vis used to power up the I2C port.
The boost circuit is controlled by a FET and the FET can be controlled using A3.

Lets a say you have connected a sensor on the i2c port and want to turn on the sensor only when you need to read it in that case you will use the A3 to control the sensor power. This will let you save the power and everything can run off a battery.



Hi Bhaskar,

Thank you for your reply. Still a little lost here. I hooked up an I2C weather sensor, the Argon did not see it. Of course I load the I2C Scanner. By the way, I am using the Particle Web IDE. I checked the I2C 5Volts pin, I read 0 volt. I guess the I2C is not enable yet, how do I enable it? You mentioned using the A3, is that pin A3 of the Particle Argon?

Thank you.


Yes A3 of particle module. You will need to set it high in order to enable the 5V on i2c port.




A3 refuses to go HIGH. I can enable HIGH any other pin like A2, D4, etc. Any idea what could be the problem? The I2C still not working.

Thank you,


Connect the A3 to 3.3V using a wire. This will enable the i2c port
There is solder pad jumper on the board marked as A3. Move the solder pad opposite to “X” marking.

I will take a look why A3 is going high in the software.


Yes Sir, moving the solder pad did the trick. Thank you for your help.