Ole Petter R=F8nningen wrote:

> Hi all (Please excuse all lame questions, I am new to this..)
>
> I have a couple of questions I hope you can help me with
>
> 1. Does anybody know where I can find the specs for SPI??

I use the Microchip SPI for communicating with 17 PICs.
Read their specs!

>
>
> 2. I am trying to interface a PIC16C74 to multiple (5-10) other PIC's. =
I
> initially thought of using I2C, but a recent thread indicated that this=
 is
> not the way to go. So I turned to RS232. What I figured I'd do was to u=
se
> two analog multiplexers, and send TX and RX through one each. The addre=
ss
> lines would then be connected to both multiplexers. I need to be able t=
o
> wire this up in a "star" fashion. The master will poll the slaves regul=
arly,
> so there is no need to keep comms up with the slaves all the time. Does
> anyone have such a design, or know of a multiplexer that can be used? A=
s far
> as I can tell RS232 specifies "0" as -3 to -23V, and "1" as +3 to +23V =
(or
> was it the other way around? Anyway). I have not been able to find the =
exact
> electrical specifications on the 16C74A (anybody, jump in, please). I
> originally looked at a 4051 (CD4051BCN from Fairchild, to be exact.), b=
ut it
> seems it can only handle 0-6V..
>
> Thanks!
>
> Ole Petter
>
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