Well I got it to work.  Turns out that something in the code was over
writing the TRISC register on one of the slaves with random stuff.  This
typically resulted in the SDI line on the slave being driven instead of
passive.  The clock line would get driven too.  So I got the garbage one
would expect with such gremlins.  I changed some things around and the
TRISC register stopped getting clobbered.  Everything works like a charm
know.  I have a 4x20 LCD and a 4 char LED display on the slave 16c62 and I
can drive them fine from the master 16c74.  I haven't read anything back
from the slave yet, but will be in the near future.

Kevin "two outputs don't make good data" Russell

----------
> From: Kevin Russell <kevin.russell@null.net>
> To: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
> Subject: Re: SPI slave-mode on the 16c6X
> Date: Tuesday, March 18, 1997 7:01 PM
>
> I have *not* been able to get it to work.  I have a 16c74 acting as a
> master, and two 16c62's acting as slaves in my design and I can not make
> them work.  If I just twiddle the clock link I can get some garbage, but
I
> can't seem to make anything intelligent happen.  I am using the CCS PCM
> compiler and have spent a considerable amount of time pouring over the
code
> and can't seem to figure out what is wrong.  That is if the parts work as
> described in the data sheets.  BTW, I did make a small mistake in
> specifiying the clock rate on the slave parts in the PCM spi_setup line.
> That results in the part being configured for I2C!
>
> Kevin Russell
>
>
> ----------
> > From: Don Raines <donster@JUNO.COM>
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: SPI slave-mode on the 16c6X
> > Date: Tuesday, March 18, 1997 1:06 PM
> >
> > Has anyone actually gotten SLAVE mode SPI working on the 16c6X?
> >
> > (I'll wait for at least 1 'yes' before continuing this question...)
> >
> > Thanks,
> > Don Raines