I haven't studied the data sheet recently, but make sure that RA1 is
pulled up by a resistor, as it is probably an open collector, meaning it
can only pull low, it can't pull high.  Once low,depening on what it's
connected to, it may never go high again, ruining your IIC  clock signal.

-Adam

Alex Oca wrote:

> Hello Guys
>
> We have a big, big problem. We have a application with 16C74 that has
> an IIC
> bus to communicate to others devices and another IIC to communicate
> with an
> EEPROM. For the first one we use RC3-RC4 and we have no problem. The
> second
> one is done with RA0 (SCL) and RA1 (SDA) and also, it share the RA
> port with
> an output pin (RA2). Everything is Ok until a data is written into RA
> port
> to change the output to any digital status (high or low). After that, we
> lose the control over the EEPROM, we can not read or write any data
> from or
> to the EEPROM. There is no change of the digital levels of both
> signals (SCL
> & SDA).
> We will appreciate any help. Sorry our english.
>
> Regards
>
> Alex & Kpot
>
>
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