I2C Bus (max wire lenght)

[NavMicroSystems]

I'm working on a project with 18F452 and a number of (16) I2C I/O Expanders (PCF8574).
This would give additional 128 I/O Ports.

The PCF8574's will be on separate PCBs each.
I'm planning to use a ribbon cable to connect all the Boards to the I2C bus.

Do you have any experience regarding the max cable length for I2C communication?

regards

Ralph

[mister_e]

Hi ralph,
i never experiment i2c long distance task but i heard a few time 9-12 meters depending clock speed and load.

[Melanie]

See link posted in Documentation Section.

[Luciano]

Using the Philips P82B715 I2C extender on long cables.
(Read first AN444.pdf).

P82B715 I²C bus extender:
http://www.semiconductors.philips.com/pip/P82B715PN.html

P82B715 Datasheet:
http://www.semiconductors.philips.com/acrobat_download/datasheets/P82B715_6.pdf

P82B715 Application Note:
http://www.semiconductors.philips.com/acrobat_download/applicationnotes/AN444.pdf

One mile long I2C communication using the P82B715:
http://www.semiconductors.philips.com/acrobat_download/applicationnotes/AN452.pdf


Where to buy in small quantities:

http://www.distrelec.com Art.No: 649003
http://www.schuricht.de Art.No: 649003

Regards

[NavMicroSystems]

Thanks to all of you for your response.

I have done some tests and it looks good so far.

Max wire lenght I need for this project is about 3m.
(But in a "noisy" environment)

I promise to write a short report after I have finished the project.

(I'm dealing with a total 150+ I/O lines on a "small" PIC 18F452)

Regards

Ralph

[mister_e]

In a noisy environement. the only thing that i can suggest is to use multiple pair shielded each other in a shielded cable. and wish you good luck.`;)


regards

[NavMicroSystems]

As promised here the first results,

the MCU Board:

[NavMicroSystems]

16 Bit I2C Input:

[NavMicroSystems]

16 Bit I2C Output: