I purchased a Navio2 and have a question regarding the default configuration of the I2C bus. When looking at the bottom of the board, I see pads for resistors which are labeled R12 and R11 which would pull up and pull down the SCL and SDA lines, but no resistors. I wanted to confirm that these are left blank intentionally, for the user to add their own if necessary. Are there any recommendations for adding our own resistors?
I have used the i2C plug with an external compass (from 2nd GPS on UART) and it works without modification.
Welcome to the forum!
I can confirm that R11 and R12 were left blank intentionally. If you’re using Navio2 with Raspberry Pi, you don’t need to add your resistors. I can’t comment much about the custom setup, but maybe someone had an experience with it.
Not sure about this setup, but in general I2C requires only one pullup per line, usually close to the controller. Maybe with your setup there already are pullup resistors.
There are also “unconventional” solutions where the controller takes care using the internal pullup.