I agree, Olin. I've had trouble implementing the PIC i2C module as well.
The cap on the SD line was noticed for me as well (about 15pF was needed).
I have some good bit-banged routines that work great, though.

--Bob

At 03:06 PM 7/11/2003 -0400, you wrote:
> > It thus appears that the PIC16F876A is having trouble acting as an I2C
> > slave.  I have tried multiple PIC16F876A chips, but all have the same
> > problem.  I am hoping someone here may know what the problem is before I
> > start doing some serious debugging work.  Are there any known I2C
> > problems with the PIC16F876A chips?  I did check the Microchip website
> > and found no meantion of any problems.  I have also consulted the
> > PIC16F876 to PIC16F876A guide.  Has anyone had a similar experience?
>
>I don't know about the A version of these chips, but the older versions
>have the nasty habit of sampling the ACK bit on the wrong edges of SCK in
>master mode.  This causes a race condition with a few pF or nS one way or
>the other making a difference in whether the master sees the ACK or not.
>I had a case where it worked with a scope probe attached but not without.
>There are also other gotchas in the MSSP implementation that Microchip
>seems reluctant to admit to.
>
>
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>
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