Messages in this thread | | | From | David Woodhouse <> | Date | 16 Mar 2003 10:05:31 +0000 | Subject | RE: RS485 communication |
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On Sun, 2003-03-16 at 00:56, Alan Cox wrote: > RS485 supports CDMA, thats more than enough to implement ppp nicely, all > you have to do is a little abuse in the app or driver layer to block > sending when carrier is asserted
Note you don't need any separate lines for this. If someone else is transmitting a zero while you are also transmitting a zero, that's fine and you didn't stomp on each other. If someone else is transmitting a zero while you are transmitting a one, you won and a one was transmitted, and they back off. If they transmit a one while you transmit a zero, then they won :)
That's how CAN does it, IIRC. I don't believe it actually requires synchronous clocks.
-- dwmw2
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