Are there pullup resistors on the Notecard I2C lines already? Or do they need to be added externally?
Hey Pat, good question. There are pullups on the SDA/SCL lines of the Notecard, so you should be ok at the prototype phase using the pullups already on the board. If you’re looking to spin your own board for a pilot or deployment, we suggest putting a scope on the SDA and SCL lines of your design just to make sure the signals perform as you expect, and add additional pullups, as needed.
Hey, quick followup question: in the Notecarrier-AE schematic v1.7.pdf I couldn’t find any hardware pullups on these lines, I could only find the 100 ohm series resistors. Are they internal pullups and do you happen to know the resistance values?
Thanks for posting. That’s a great question.
Yes. There are internal pull-ups. They are 10 kOhm.