Processor to Processor Communications via UART

MotoDan · Joined: 30 Dec 2011 Posts: 55

Hello all,

I'm considering using the built-in UARTs to communicate between a single "master" PIC and multiple "slave" PICs - similar to RS-485. All devices will be located within 2 ft of each other and I plan to connect RX/TX lines directly - without any transceivers. Since only one PIC will be transmitting at a time, I plan on being able to tri-state the inactive TX lines. Is there any problem with this approach?

Thanks in advance!
Dan

temtronic · Posted: Fri May 04, 2012 7:36 pm

Well, it should only take you a few hours to cut code,breadboard the PICs and see what happens. You should have some kind of background timer to be sure the slaves are always set to HiZ mode unless commanded to transmit and then set HiZ when done or timedout.

I'm also assuming they're powered from a common power supply so logic levels and grounding won't be an issue.

temtronic · Posted: Fri May 04, 2012 7:37 pm

Come to think of it, CCS gave an example of this in their manual back in '99. Might be in the current issue, haven't looked.

dyeatman · Joined: 06 Sep 2003 Posts: 1933 Location: Norman, OK

Yep, still there on page 335.
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MotoDan · Joined: 30 Dec 2011 Posts: 55

Thanks for the replies. I did find the reference in the CCS manual.
Dan