Just a question regarding SparkFun Qwiic Scale - NAU7802: to save as much power as possible, is it OK to remove the pullup resistors R2/R3 (2.2k)? In the datasheet https://cdn.sparkfun.com/assets/e/c/8/7 … t_V1.7.pdf , Section 9.4, no pullup resistors are included in the schematic. The MCU is pretty close to the NAU7802 in my case.
For I2C, you must have pullup resistors. I2C is an open collector/open drain bus; the devices connected to it can only pull the lines low. The pullup resistors are used to generate the logic “1”. They don’t need to be on the QWIIC scale board; they can be anywhere on the bus. To save power, you can probably change them to larger value resistors (say 4k7 or even 10k). Also, make sure there is only one set of pullup resistors on the bus; multiple ones will lower the effective resistance and will consume more power.
/mike
The MCU board I use already has some pullup resistors (2 x 4.7k; see image), so I understand your answer that should be enough.
