Long Distance I2C

[Mr.NCK]

Hi

I need a suggestion. We are like to try a long-distance I2C  communication between the sensor & Nrf5340  that is we need to connect  1.5 meters of cable between them. So, before design, we need clarification about this. Is it possible to do this?. If this is possible. what are the things need to take care of?

Thanks & Regards

Navin

[JONATHAN LL]

I will look in to this, but there are more factors to consider. What communication rate, what is the total capacitance of the wires at that length? Are the wires shielded or not?

Regards,
Jonathan

[Mr.NCK]

Hi Jonathan,

 The Sensor which we going to use is mlx90614. It uses SMBus communication which uses 100khz (Standard bitrate) as communication rate. for wire, we need to use nearly 2 meters of length. So, we are expecting some suggestions for wire from you.

Thanks & Regards

Navin

  

[Mr.NCK]

Hi Jonathan,

Are you there??

[JONATHAN LL]

Hi,

Yes, i am here, but i cant recommend any specific type of wire. I2C is not designed for long distance communication. 


The I²C specification allows a line capacitance of 400 pF at most. https://infocenter.nordicsemi.com/topic/ps_nrf5340/twim.html?cp=3_0_0_6_35_9#concept_twim_timings 

There are some a bunch of forums discussing best practise on how to go about this solution but we at Nordic do not have any explicit experience with this so i can not recommend anything specific. I dont know how noisy the environment is in your application so difficult to say, but shielded wires could be a good idea to reduce chase of extra noise introduces to the system. Capacitance of the wires might be the biggest issues here so different gauge wires will have different max lengths.  

bus - Best way to do I2C/TWI over long distance - Electrical Engineering Stack Exchange 
Sending i2c over 7 meters | All About Circuits
I2C Long Distance - Using Arduino / Networking, Protocols, and Devices - Arduino Forum
I2C FAQ - EmSA (esacademy.com) 
Maximum I2C Bus Length? - Electrical Engineering Stack Exchange


Extender options
Extending I2C Communication Distance with the DS28E17 (maximintegrated.com)
75016527.pdf (nxp.com)

If you have some development kits you could set up your own test and see how well different lengt and type of wires gauge preform in the given environment. 


Regards,
Jonathan

[Mr.NCK]

Thank you Jonathan