>It's because I'm using a very simple, cheap and basic
>PIC, there is no parallel, i2c or spi in it.
>Each PIC has it own task to settle and process.
>However, both need to communicate and use some of the
>processed data in a fast manner.
>Any idea to control and signal the control pin to each
>other that data is ready and in-sync is great.

Use a protocol like the TI-80 series calculators use to talk to each other.
This can be used bidirectionally, and does not require the use of timers in
the PIC unless you want to check for a timeout condition if things get
disconnected.

Look in the archives at http://www.piclist.com for the following message

From: Wesley Moore <wmoore@CS.RMIT.EDU.AU>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Subject:      Re: Interfacing TI calc to PIC
Date: 26 April 2000 14:17

and this will give you quite clear description of how the hardware interface
works.

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