Length of I2C and One Wire Buses (CMM2)

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Mixtel90 Guru Joined: 05/10/2019 Location: United Kingdom Posts: 8964	Posted: 12:26pm 18 Feb 2021       It depends on your cable and site. Max bus capacitance can be regarded as 400pF for use at 100kHz. For long distances you may need low capacitance cable to keep it below that. Also, pull-up resistor value changes the range. It can be advantageous to use constant current sources rather than resistors. This NXP document has a lot of info: http://www.nxp.com/documents/user_manual/UM10204.pdf