I2C start signal not correct on oscilloscope

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I2C start signal not correct on oscilloscope

by Risha

I2C problem using PIC18f4580 as master and PIC18f4550 as slave.

Hi folks,

my clock line is correct ie scl but sda wave form is not rite when I probe it using oscilloscope. its just noise. I am using PIC18f4580 as master and PIC18f4550 as slave.

Probing the signals on the master side.
for generating start signal setting the start enable bit and waiting or polling for the transfer to complete. The irony here is it completes but not show the rite waveforms on oscilloscope.

regards,
risha

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I2C start signal not correct on oscilloscope

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Sep 20, 2007

How are you triggering the scope
by: John Main

To previous commenter:

The originator of the question can enter an email address to be notified of changes whenever a comment is made. As you probably saw after entering a comment you can click a check box to be notified (adding your email address to receive notification).

Risha how are you triggering the scope?

Clock will be continuous and you probably need to trigger on the start message condition. That is more a job for a logic analyser (or make a trigger detect using a PIC ;-)

Maybe you should upload a picture to show what is going on as it's difficult to help without circuit or picture etc. even the scope type could help.

Best Regards John Main

P.S. upload address is in the help on the main problem page.

Sep 20, 2007

I2C PROBLEM
by: Anonymous

any reply or guidance here . if solutions are posted to this question . how to find out?

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I2C start signal not correct on oscilloscope

Comments for I2C start signal not correct on oscilloscope

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I2C start signal not correct on oscilloscope