I2C question about pullup resistors

Hardware
1

Are there pullup resistors on the Notecard I2C lines already? Or do they need to be added externally?

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2

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.

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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?

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4

Thanks for posting. That’s a great question.

Yes. There are internal pull-ups. They are 10 kOhm.

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