Home/Support/Support Forum/I2C Pull Up Resistor Selection
New and improved user forum site going live on 12/6 (All users will need to reset their password when the new forum is active)

I2C Pull Up Resistor Selection

0 votes
I am working on one design with Xbee3.
I want to add the option for the I2C communication, but wondering what would be the best pullup reistor values I could use.

I do not find any datasheet that specifiy the requirement.

I have XB3-24Z8PT-J and XB3-24Z8PT models
asked Sep 28, 2020 in XBee3 ZigBee by ksonone New to the Community (0 points)

Please log in or register to answer this question.

2 Answers

0 votes
Leave the Pull up resistors at defaults for the two lines.

answered Sep 28, 2020 by mvut Veteran of the Digi Community (15,515 points)
Thank you, Mvut, for your response. The link you have provided is talking about software implementation.

I am looking for hardware implementation, as every microcontroller has a specific requirement for the I2C hardware implementation.

The following is the one reference document I am looking into.
The internal resistors on these pins are set via the firmware to be enabled, pull up or down.
0 votes
I have a I2C air pressure sensor that I am using with the Xbee3. I was able to successfully get it to communicate using 10kohm pull up resistors as follows:

10kohm btw. SDA --> VCC
10kohm btw. SCL --> VCC

Even using the I2C settings via micropython and noting the "automatic" pin settings I still had to add the external pullup resistors to make the sensor work properly.
answered Sep 29, 2020 by backpacker87 Community Contributor (52 points)
Unstable i2c readings