> That's right. You can use individual port pins (the way to go with only two
> slaves) or you can use a decoder chip such as an 'HC138 if you have a lot
> of slaves. Using a decoder chip has the added benefit that it automatically
> enforces only one slave active on the bus at a time.

I understand how SPI works now but I have a one more question. I just noticed
that the seeprom I wanted to use (the 93LC56) isn't SPI, but Microwire. And for
the digital thermometer, I know its 3-wire interface but not sure whether it
 uses
SPI or Microwire.
Anyway, what I would like to know is, can I use the PIC16C74's SPI module to
control microwire devices like the 93LC56 and so on?

It seems like SPI and Microwire resembles a lot. They both have in common the
SCL, SDI, SDO pins... what's the big difference?

Thanks again,
Jean-Francois