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rgovindappa9
rgovindappa9
Associate II
March 22, 2011
Question

Maximum Cable length for I2C protocol in STM8S

  • March 22, 2011
  • 2 replies
  • 1944 views
Posted on March 22, 2011 at 08:21

Maximum Cable length for I2C protocol in STM8S

#i2c
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2 replies

Andrew Neil
Andrew Neil
Super User
May 17, 2011
Posted on May 17, 2011 at 15:12

I2C has no specific limit on cable length as such, but there is a limit on total capacitance.

 

Clearly, for any given cable type, this will limit the length of that particular cable.

This has nothing to do with the STM8; it is defined in the I2C specifications - available from NXP:

http://www.nxp.com/acrobat/usermanuals/UM10204_3.pdf

Bus ''Repeater'', ''Hub'', and ''Extender'' chips are available for making ''long'' and/or complex I2C busses...

http://ics.nxp.com/support/i2c.usage/

http://ics.nxp.com/support/interface/

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
rgovindappa9
rgovindappa9Author
Associate II
May 17, 2011
Posted on May 17, 2011 at 15:12

@ neil.andrew

Thanks for your reply. It seems there are several factors which are to be considered for I2C cable length like frequency(lower the better for long lengths), capacitance the following link is also pertinent to the topic

www.nxp.com/documents/application_note/AN10658.pdf

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