At 04:41 AM 8/19/97 -0800, you wrote:
>> 1) How few pins can I get away with?
>
>    For example:
>
>    Your Master PIC controls the Slave PIC's MCLR line.  The Master
>    normally keeps the Slave's MCLR line high (out of reset).  When
>    the Master wants to send a message, it pulls the Slave's MCLR
>    line low, then pulls it high for a short time before pulling it
>    low, then high again.
>
>    The "message" is the time between MCLR-low pulses.

OK, that's got me interested.. the SLAVE's second job out of reset is to
increment a register, so that next time it comes out of reset, the first
job it has is testing that same register for the message sent to it... So
far so good. What's the approved method of determining if it's a valid
message, or just random powerup garbage?

Cheers,

Bob

http://www.bobblick.com/