How to slow down I2C below 50kHz?

kender · Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley

Colleagues,

Is it possible to slow down a frequency of the I2C on the PIC without writing my own bit-banging code? I have to deal with a tough case of an isolation barrier, where the difference between the grounds on different sides will be reaching 10kV. I2C bus has to cross this barrier. Unfortunately optocouplers which can handle 5kV have a propagation delay on the order of 5us, which is probably too much even for the 100kHz I2C.

Thanks,
Nick

rwyoung · Joined: 12 Nov 2003 Posts: 563 Location: Lawrence, KS USA

The latest version of the compiler have an additional parameter for the #use i2c line where you can set the speed. Look at the readme.txt for the compiler.

I haven't tried it but it might get you started.
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

What is your PIC and your crystal frequency ?
See this post:
http://www.ccsinfo.com/forum/viewtopic.php?t=3616&highlight=i2c+baud+rate