Hi

That is encouraging.  I don't suppose the code will make it into public
domain... will it?  Do the 14000 have  dedicated I2C hardware?

Charles

>Date:         Mon, 12 Jan 1998 09:40:20 -0800
>Reply-To:     pic microcontroller discussion list
<PICLIST@MITVMA.MIT.EDU>
>From:         Dave Reinagel <daver@AUSPEX.COM>
>Subject:      Re: PIC14000 and I2C
>To:           PICLIST@MITVMA.MIT.EDU
>
>John,
>        Just a word of encouragement; I have recently finished a
project
>where 1 PIC14000 was a master and 4 PIC14000 were the slaves, and it
works
>and is now being released to production, so I know it can be done.  I
used
>PORTC<7:6>, and did it all in assembly.  I found a few strange things
dur-
>ing debug.  I run my slaves in interrupt mode, and at the end of each
>write sequence, I got an interrupt indicating that a read operation was
>required, which was a bogus event.  To fix that, I made a state machine
to
>detect a read interrupt immediately after the end of a write operation,
to
>dump the reading, and all my problems went away.
>
>        But another warning:  while in design verification, the PIC's
power
>was varied, and we found that the ADC reading, particularly the
calculated
>temperature value, was way off (particularily as the voltage went below
4
>volts).  After a day of testing, we found very strangely that if we
used
>the SREFHI signal as the bandgap reading, and used the bandgap reading
for
>SREFHI, the problem almost completely went away.  (I use all of Port A
for
>analog inputs.)  I contacted Microchip about this, and they couldn't
immed-
>iately reproduce it, so they want me to prove this problem to them; my
boss
>says that after the project is complete, we will revisit this and try
to
>make a simple proof of the problem.  But you may want to check this out
for
>your project.
>
>Dave Reinagel
>Auspex Systems, Inc.
>


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